Big-Data-HPC-Platform/ecl/hqlcpp/hqlresource.cpp

/*##############################################################################

    Copyright (C) 2011 HPCC Systems.

    All rights reserved. This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
############################################################################## */
#include "platform.h"
#include "jlib.hpp"

#include "hqlexpr.hpp"
#include "hqlattr.hpp"
#include "hqlmeta.hpp"
#include "hqlutil.hpp"
#include "hqlcpputil.hpp"
#include "hqlthql.hpp"
#include "hqlcatom.hpp"
#include "hqlfold.hpp"
#include "hqlcerrors.hpp"
#include "hqltrans.ipp"
#include "hqlpmap.hpp"
#include "hqltcppc.ipp"
#include "hqlttcpp.ipp"

#include "hqlresource.ipp"
#include "../../thorlcr/thorutil/thbufdef.hpp"

#define MINIMAL_CHANGES
#define MAX_INLINE_COMMON_COUNT 5
//#define TRACE_RESOURCING
//#define VERIFY_RESOURCING
//#define SPOT_UNCONDITIONAL_CONDITIONS

#define DEFAULT_MAX_SOCKETS 2000 // configurable by setting max_sockets in .ini
#define DEFAULT_TOTAL_MEMORY ((1024*1024*1800)-DEFAULT_LARGEMEM_BUFFER_SIZE)
#define FIXED_CLUSTER_SIZE 400
#define MEM_Const_Minimal (1*1024*1024)
#define DEFAULT_MAX_ACTIVITIES  100

//=== The following provides information about how each kind of activity is resourced ====

static void setHashResources(IHqlExpression * expr, CResources & resources, const CResourceOptions & options)
{
    if (options.useMpForDistribute)
    {
        unsigned memneeded = MEM_Const_Minimal+resources.clusterSize*4*DISTRIBUTE_SINGLE_BUFFER_SIZE+DISTRIBUTE_PULL_BUFFER_SIZE;
        resources.set(RESslavememory, memneeded).set(REShashdist, 1);
    }
    else
    {
        resources.set(RESslavememory, MEM_Const_Minimal+DISTRIBUTE_PULL_BUFFER_SIZE).set(REShashdist, 1);
        resources.setManyToManySockets(2);
    }
}


//MORE: Use a single function to map an hqlexpression to an activity kind.
void getResources(IHqlExpression * expr, CResources & resources, const CResourceOptions & options)
{
    //MORE: What effect should a child query have?  Definitely the following, but what about other resourcing?
    if (options.isChildQuery || queryHint(expr, lightweightAtom))
    {
        resources.setLightweight();
        return;
    }

    bool isLocal = isLocalActivity(expr);
    bool isGrouped = isGroupedActivity(expr);
    switch (expr->getOperator())
    {
    case no_join:
    case no_selfjoin:
    case no_denormalize:
    case no_denormalizegroup:
        if (isKeyedJoin(expr) || expr->hasProperty(_lightweight_Atom))
            resources.setLightweight();
        else if (expr->hasProperty(lookupAtom))
        {
            if (expr->hasProperty(fewAtom))
            {
                resources.setLightweight().set(RESslavememory, MEM_Const_Minimal+LOOKUPJOINL_SMART_BUFFER_SIZE);
                resources.setManyToMasterSockets(1);
            }
            else
            {
                resources.setHeavyweight().set(RESslavememory, MEM_Const_Minimal+LOOKUPJOINL_SMART_BUFFER_SIZE);
                resources.setManyToMasterSockets(1);
            }
        }
        else if (expr->hasProperty(hashAtom))
        {
            resources.setHeavyweight();
            setHashResources(expr, resources, options);
        }
        else
        {
            resources.setHeavyweight().set(RESslavememory, MEM_Const_Minimal+SORT_BUFFER_TOTAL+JOINR_SMART_BUFFER_SIZE);
            if (!isLocal)
            {
#ifndef SORT_USING_MP
                resources.setManyToManySockets(2);
#endif
            }
        }
        break;
    case no_dedup:
        if (isGrouped || (!expr->hasProperty(allAtom) && !expr->hasProperty(hashAtom)))
        {
            resources.setLightweight();
            if (!isGrouped && !isLocal)
            {
                resources.set(RESslavememory, MEM_Const_Minimal+DEDUP_SMART_BUFFER_SIZE);
                resources.setManyToMasterSockets(1);
            }
        }
        else if (isLocal)
        {
            resources.setHeavyweight().set(RESslavememory, MEM_Const_Minimal+DEDUP_SMART_BUFFER_SIZE);
            //This can't be right....
            //resources.setManyToMasterSockets(1);
        }
        else
        {
            //hash dedup.
            resources.setHeavyweight();
            setHashResources(expr, resources, options);
        }
        break;
    case no_rollup:
        resources.setLightweight();
        if (!isGrouped && !isLocal)
        {
            resources.set(RESslavememory, MEM_Const_Minimal+DEDUP_SMART_BUFFER_SIZE);
            //MORE: Is this still correct?
            resources.setManyToMasterSockets(1);
        }
        break;
    case no_distribute:
    case no_keyeddistribute:
        resources.setLightweight();
        setHashResources(expr, resources, options);
        break;
    case no_shuffle:
        if (expr->hasProperty(manyAtom))
            resources.setHeavyweight();
        else
            resources.setLightweight();
        break;
    case no_sort:
        if (isGrouped)
        {
            if (expr->hasProperty(manyAtom))
                resources.setHeavyweight();
            else
                resources.setLightweight();
        }
        else if (expr->hasProperty(fewAtom) && isLocal)
            resources.setLightweight();
        else if (isLocal)
            resources.setHeavyweight();
        else
        {
            resources.setHeavyweight();
#ifndef SORT_USING_MP
            resources.setManyToManySockets(2);
#endif
        }
        break;
    case no_topn:
        resources.setLightweight();
        break;
    case no_pipe:
        //surely it should be something like this.
        resources.setLightweight().set(RESslavesocket, 1);
        break;
    case no_table:
        {
            IHqlExpression * mode = expr->queryChild(2);
            if (mode && mode->getOperator() == no_pipe)
            {
                resources.setLightweight().set(RESslavesocket, 1);
            }
            else
            {
                resources.setLightweight();
                if (expr->hasProperty(_workflowPersist_Atom) && expr->hasProperty(distributedAtom))
                    setHashResources(expr, resources, options);         // may require a hash distribute
            }
            break;
        }
    case no_output:
        {
            IHqlExpression * filename = expr->queryChild(1);
            if (expr->hasProperty(_spill_Atom))
            {
                //resources.setLightweight();   // assume no resources(!)
            }
            else if (filename && filename->getOperator() == no_pipe)
            {
                resources.setLightweight().set(RESslavesocket, 1);
            }
            else if (filename && !filename->isAttribute())
            {
                resources.setLightweight();
            }
            else
            {
                resources.setLightweight().set(RESslavememory, WORKUNITWRITE_SMART_BUFFER_SIZE);
            }
            break;
        }
    case no_distribution:
        resources.setLightweight().set(RESmastersocket, 16).set(RESslavesocket, 1);
        break;
    case no_aggregate:
    case no_newaggregate:
        {
            IHqlExpression * grouping = queryRealChild(expr, 3);
            if (grouping)
            {
                //Is this really correct???
                resources.setLightweight();
                setHashResources(expr, resources, options);
            }
            else
            {
                resources.setLightweight();
                //if (!isGrouped)
                //  resources.set(RESmastersocket, 16).set(RESslavesocket, 1);
            }
        }
        break;
    case no_hqlproject:
        resources.setLightweight();
        //Add a flag onto count project to indicate it is a different variety.
        if (expr->hasProperty(_countProject_Atom) && !isLocal)
            resources.set(RESslavememory, COUNTPROJECT_SMART_BUFFER_SIZE);
        break;
    case no_enth:
        resources.setLightweight();
        if (!isLocal)
            resources.set(RESslavememory, CHOOSESETS_SMART_BUFFER_SIZE);
        break;
    case no_metaactivity:
        if (expr->hasProperty(pullAtom))
            resources.setLightweight().set(RESslavememory, PULL_SMART_BUFFER_SIZE);
        break;
    case no_setresult:
    case no_extractresult:
    case no_outputscalar:
        resources.setLightweight();//.set(RESmastersocket, 1).set(RESslavesocket, 1);
        break;
    case no_choosesets:
        resources.setLightweight();
        if (!isLocal || expr->hasProperty(enthAtom) || expr->hasProperty(lastAtom))
            resources.set(RESslavememory, CHOOSESETS_SMART_BUFFER_SIZE);
        break;
    case no_iterate:
        resources.setLightweight();
        if (!isGrouped && !isLocal)
            resources.setManyToMasterSockets(1).set(RESslavememory, ITERATE_SMART_BUFFER_SIZE);
        break;
    case no_choosen:
        resources.setLightweight().set(RESslavememory, FIRSTN_SMART_BUFFER_SIZE);
        break;
    case no_spill:
    case no_spillgraphresult:
        //assumed to take no resources;
        break;
    case no_addfiles:
    case no_merge:
        {
            resources.setLightweight();
            unsigned bufSize = FUNNEL_PERINPUT_BUFF_SIZE*expr->numChildren();
            if (bufSize < FUNNEL_MIN_BUFF_SIZE) bufSize = FUNNEL_MIN_BUFF_SIZE;
            resources.set(RESslavememory, MEM_Const_Minimal+bufSize);
            break;
        }
    case no_compound:
        //MORE: Should really be the total resources for the lhs...  Really needs more thought.
        break;
    case no_libraryselect:
        //Do not allocate any resources for this, we don't want it to cause a spill under any circumstances
        break;
    case no_split:
        //Should really be included in the cost....
    default:
        resources.setLightweight();
        break;
    }
}


CResources & CResources::setLightweight()                           
{ 
    return set(RESslavememory, 0x10000).set(RESactivities, 1); 
}


CResources & CResources::setHeavyweight()
{ 
    return set(RESslavememory, 0x100000).set(RESheavy, 1).set(RESactivities, 1); 
}


//-------------------------------------------------------------------------------------------


const char * queryResourceName(ResourceType kind)
{
    switch (kind)
    {
    case RESslavememory:    return "Slave Memory";
    case RESslavesocket:    return "Slave Sockets";
    case RESmastermemory:   return "Master Memory";
    case RESmastersocket:   return "Master Sockets";
    case REShashdist:       return "Hash Distributes"; 
    case RESheavy:          return "Heavyweight";
    case RESactivities:     return "Activities";
    }
    return "Unknown";
}

inline ResourcerInfo * queryResourceInfo(IHqlExpression * expr) { return (ResourcerInfo *)expr->queryBody()->queryTransformExtra(); }

inline bool isResourcedActivity(IHqlExpression * expr)
{
    ResourcerInfo * extra = queryResourceInfo(expr);
    return (extra && (extra->isActivity || extra->containsActivity));
}

bool isWorthForcingHoist(IHqlExpression * expr)
{
    loop
    {
        switch (expr->getOperator())
        {
        case no_selectnth:
        case no_filter:
        case no_newaggregate:
            if (isResourcedActivity(expr->queryChild(0)))
                return true;
            break;
        default:
            return false;
        }
        expr = expr->queryChild(0);
    }
}


void CResources::add(const CResources & other)
{
    for (unsigned i = 0; i < RESmax; i++)
        resource[i] += other.resource[i];
}

bool CResources::addExceeds(const CResources & other, const CResources & limit) const
{
    for (unsigned i = 0; i < RESmax; i++)
    {
        if (resource[i] + other.resource[i] > limit.resource[i])
        {
            //DBGLOG("Cannot merge because limit for %s exceeded (%d cf %d)", queryResourceName((ResourceType)i), resource[i] + other.resource[i], limit.resource[i]);
            return true;
        }
    }
    return false;
}

StringBuffer & CResources::getExceedsReason(StringBuffer & reasonText, const CResources & other, const CResources & limit) const
{
    bool first = true;
    for (unsigned i = 0; i < RESmax; i++)
    {
        if (resource[i] + other.resource[i] > limit.resource[i])
        {
            if (!first) reasonText.append(", ");
            first = false;
            reasonText.appendf("%s (%d>%d)", queryResourceName((ResourceType)i), resource[i] + other.resource[i], limit.resource[i]);
        }
    }
    return reasonText;
}

bool CResources::exceeds(const CResources & limit) const
{
    for (unsigned i = 0; i < RESmax; i++)
    {
        if (resource[i] > limit.resource[i])
            return true;
    }
    return false;
}

void CResources::maximize(const CResources & other)
{
    for (unsigned i = 0; i < RESmax; i++)
    {
        if (resource[i] < other.resource[i])
           resource[i] = other.resource[i];
    }
}

CResources & CResources::setManyToMasterSockets(unsigned numSockets)
{
    set(RESslavesocket, numSockets);
    set(RESmastersocket, numSockets * clusterSize);
    return *this;
}

CResources & CResources::setManyToManySockets(unsigned numSockets)
{
    return set(RESslavesocket, numSockets * clusterSize);
}

void CResources::sub(const CResources & other)
{
    for (unsigned i = 0; i < RESmax; i++)
        resource[i] -= other.resource[i];
}

//===========================================================================

inline bool isAffectedByResourcing(IHqlExpression * expr)
{
    switch (expr->getOperator())
    {
    case no_record:
    case no_constant:
    case no_attr:
        return false;
    }
    return true;
}


bool isSimpleAggregateResult(IHqlExpression * expr)
{
    //MORE: no_extractresult is really what is meant
    if (expr->getOperator() != no_extractresult)
        return false;
    IHqlExpression * value = expr->queryChild(0);
    if (value->getOperator() != no_datasetfromrow)
        return false;
    //MORE: This currently doesn't hoist selects from nested records, but not sure there is a syntax to do that either.
    IHqlExpression * ds = value->queryChild(0);
    if (!isSelectFirstRow(ds))
        return false;
    ds = ds->queryChild(0);
    if (ds->getOperator() != no_newaggregate)
        return false;
    return true;
}

bool lightweightAndReducesDatasetSize(IHqlExpression * expr)
{
    switch (expr->getOperator())
    {
    case no_hqlproject:
    case no_newusertable:
        return reducesRowSize(expr);
    case no_dedup:
        if (isGroupedActivity(expr) || (!expr->hasProperty(allAtom) && !expr->hasProperty(hashAtom)))
            return true;
        break;
    case no_aggregate:
    case no_newaggregate:
        {
            IHqlExpression * grouping = queryRealChild(expr, 3);
            if (grouping)
                return false;
            return true;
        }
    case no_rollupgroup:
    case no_rollup:
    case no_choosen:
    case no_choosesets:
    case no_enth:
    case no_sample:
    case no_filter:
    case no_limit:
    case no_filtergroup:
        return true;
    case no_group:
        //removing grouping will reduce size of the spill file.
        if (expr->queryType()->queryGroupInfo() == NULL)
            return true;
        break;
    }
    return false;
}


bool heavyweightAndReducesSizeOrSkew(IHqlExpression * expr)
{
    switch (expr->getOperator())
    {
    case no_aggregate:
    case no_newaggregate:
        {
            //more; hash aggregate?
            break;
        }
    case no_distribute:
        return true;
    }
    return false;
}

//---------------------------------------------------------------------------

IHqlExpression * CResourceOptions::createSpillName(bool isGraphResult)
{
    if (isGraphResult)
        return getSizetConstant(nextResult++);

    StringBuffer s;
    s.append("~spill::");
    getUniqueId(s);
    if (!mangleSpillNameWithWuid)
        return createConstant(s.str());
    s.append("_");
    if (filenameMangler)
    {
        s.append(filenameMangler);
        return createConstant(s.str());
    }

    ITypeInfo * type = makeStringType(UNKNOWN_LENGTH, NULL, NULL);
    return createValue(no_concat, type, createConstant(s.str()), createValue(no_wuid, LINK(type)));
}

//---------------------------------------------------------------------------

static bool isIndex(IHqlExpression * expr)
{
    switch (expr->getOperator())
    {
    case no_keyindex:
    case no_newkeyindex:
        return true;
    }
    return false;
}

IHqlExpression * appendUniqueAttr(IHqlExpression * expr)
{
    return replaceOwnedProperty(expr, createUniqueId());
}


bool queryAddUniqueToActivity(IHqlExpression * expr)
{
    if (!isSourceActivity(expr))
        return false;
    switch (expr->getOperator())
    {
    case no_workunit_dataset:
    case no_getgraphresult:
    case no_getgraphloopresult:
    case no_xmlproject:
    case no_datasetfromrow:
    case no_rows:
    case no_allnodes:
    case no_thisnode:
    case no_select:         // it can get lost, and that then causes inconsistent trees.
        return false;
    }
    return true;
}

//---------------------------------------------------------------------------

ResourceGraphLink::ResourceGraphLink(ResourceGraphInfo * _sourceGraph, IHqlExpression * _sourceNode, ResourceGraphInfo * _sinkGraph, IHqlExpression * _sinkNode, LinkKind _linkKind)
{
    assertex(_sourceGraph);
    sourceGraph.set(_sourceGraph);
    sourceNode.set(_sourceNode);
    sinkGraph.set(_sinkGraph);
    sinkNode.set(_sinkNode);

    assertex(!sinkGraph || sinkNode);
    linkKind = _linkKind;
    trace("create");
}


ResourceGraphLink::~ResourceGraphLink()
{
    trace("delete");
}

void ResourceGraphLink::changeSourceGraph(ResourceGraphInfo * newGraph)
{
    sourceGraph->sinks.zap(*this);
    sourceGraph.set(newGraph);
    newGraph->sinks.append(*this);
    trace("change source");
}

void ResourceGraphLink::changeSinkGraph(ResourceGraphInfo * newGraph)
{
    sinkGraph->sources.zap(*this);
    sinkGraph.set(newGraph);
    newGraph->sources.append(*this);
    trace("change sink");
}


bool ResourceGraphLink::isRedundantLink()
{
    ResourcerInfo * info = queryResourceInfo(sourceNode);
    return info->expandRatherThanSpill(false);
}

void ResourceGraphLink::trace(const char * name)
{
#ifdef TRACE_RESOURCING
    PrintLog("%s: %lx source(%lx,%lx) sink(%lx,%lx) %s", name, this, sourceGraph.get(), sourceNode->queryBody(), sinkGraph.get(), sinkNode ? sinkNode->queryBody() : NULL, 
             linkKind == ConditionalLink ? "conditional" : linkKind == SequenceLink ? "sequence" : "");
#endif
}



ResourceGraphDependencyLink::ResourceGraphDependencyLink(ResourceGraphInfo * _sourceGraph, IHqlExpression * _sourceNode, ResourceGraphInfo * _sinkGraph, IHqlExpression * _sinkNode)
: ResourceGraphLink(_sourceGraph, _sourceNode, _sinkGraph, _sinkNode, UnconditionalLink)
{
}


void ResourceGraphDependencyLink::changeSourceGraph(ResourceGraphInfo * newGraph)
{
    sourceGraph.set(newGraph);
    trace("change source");
}

void ResourceGraphDependencyLink::changeSinkGraph(ResourceGraphInfo * newGraph)
{
    sinkGraph.set(newGraph);
    newGraph->dependsOn.append(*this);
    trace("change sink");
}


//---------------------------------------------------------------------------

ResourceGraphInfo::ResourceGraphInfo(CResourceOptions * _options) : resources(_options->clusterSize)
{
    options = _options;
    depth = 0;
    depthSequence = -1;
    beenResourced = false;
    isUnconditional = false;
    mergedConditionSource = false;
    hasConditionSource = false;
    isDead = false;
    startedGeneratingResourced = false;
    inheritedExpandedDependencies = false;
    cachedDependent.other = NULL;
}

ResourceGraphInfo::~ResourceGraphInfo()
{
}

bool ResourceGraphInfo::addCondition(IHqlExpression * condition)
{
    if (conditions.find(*condition) == NotFound)
    {
        conditions.append(*LINK(condition));

#ifdef SPOT_UNCONDITIONAL_CONDITIONS
        _ATOM name = condition->queryName();
        _ATOM invName = NULL;
        if (name == trueAtom)
            invName = falseAtom;
        else if (name == falseAtom)
            invName = trueAtom;
        
        if (invName)
        {
            IHqlExpression * parent = condition->queryChild(1);
            OwnedHqlExpr invTag = createAttribute(invName, LINK(condition->queryChild(0)), LINK(parent));
            if (conditions.find(*invTag) != NotFound)
            {
                if (!parent)
                    return true;
                return addCondition(parent);
            }
        }
#endif

    }
    return false;
}

bool ResourceGraphInfo::isSharedInput(IHqlExpression * expr)
{
    IHqlExpression * body = expr->queryBody();
    if (unbalancedExternalSources.contains(*body))
        return false;
    if (queryResourceInfo(expr)->expandRatherThanSplit())
        return false;
    unsigned numUses = 0;
    ForEachItemIn(i, balancedExternalSources)
    {
        if (body == &balancedExternalSources.item(i))
            numUses++;
    }
    //NumUses could be zero if an input should be expanded, and that input is shared by another graph which also expands
    //the input.  E.g. project(meta(diskread).
    return numUses > 1;
}

void ResourceGraphInfo::addSharedInput(IHqlExpression * expr, IHqlExpression * mapped)
{
    sharedInputs.append(*LINK(expr));
    sharedInputs.append(*LINK(mapped));
}

IHqlExpression * ResourceGraphInfo::queryMappedSharedInput(IHqlExpression * expr)
{
    unsigned max = sharedInputs.ordinality();
    for (unsigned i=0; i < max; i+= 2)
    {
        if (expr == &sharedInputs.item(i))
            return &sharedInputs.item(i+1);
    }
    return NULL;
}

bool ResourceGraphInfo::allocateResources(const CResources & value, const CResources & limit)
{
    if (resources.addExceeds(value, limit))
        return false;
    resources.add(value);
    return true;
}


bool ResourceGraphInfo::containsActiveSinks()
{
    ForEachItemIn(idx, sinks)
    {
        ResourcerInfo * info = queryResourceInfo(sinks.item(idx).sourceNode);
        if (!info->expandRatherThanSpill(false))
            return true;
    }
    return false;
}

void ResourceGraphInfo::display()
{
    StringBuffer s;
    s.appendf("graph %p src(", this);
    ForEachItemIn(idxs, sources)
        s.appendf("%p ", sources.item(idxs).sourceGraph.get());
    s.append(") dep(");
    ForEachItemIn(idxd, dependsOn)
        s.appendf("%p ", dependsOn.item(idxd).sourceGraph.get());
    s.append(")");
    if (isUnconditional)
        s.append(" <unconditional>");
    DBGLOG("%s", s.str());
}

void ResourceGraphInfo::getMergeFailReason(StringBuffer & reasonText, ResourceGraphInfo * otherGraph, const CResources & limit)
{
    resources.getExceedsReason(reasonText, otherGraph->resources, limit);
}

unsigned ResourceGraphInfo::getDepth()
{
    //If no graphs have been merged since this was last called it is still valid.
    if (depthSequence == options->state.updateSequence)
        return depth;

    depthSequence = options->state.updateSequence;
    depth = 0;
    ForEachItemIn(idx, dependsOn)
    {
        ResourceGraphInfo * source = dependsOn.item(idx).sourceGraph;
        if (source->getDepth() >= depth)
            depth = source->getDepth() + 1;
    }
    ForEachItemIn(idx2, sources)
    {
        ResourceGraphInfo * source = sources.item(idx2).sourceGraph;
        if (source->getDepth() >= depth)
            depth = source->getDepth() + 1;
    }
    return depth;
}

bool ResourceGraphInfo::hasSameConditions(ResourceGraphInfo & other)
{
    if (conditions.ordinality() != other.conditions.ordinality())
        return false;
    ForEachItemIn(i, conditions)
        if (other.conditions.find(conditions.item(i)) == NotFound)
            return false;
    return true;
}

bool ResourceGraphInfo::evalDependentOn(ResourceGraphInfo & other, bool ignoreSources)
{
    ForEachItemIn(idx, dependsOn)
    {
        ResourceGraphInfo * cur = dependsOn.item(idx).sourceGraph;
        if (cur == &other)
            return true;
        if (cur->isDependentOn(other, false))
            return true;
    }
    ForEachItemIn(idx2, sources)
    {
        ResourceGraphInfo * cur = sources.item(idx2).sourceGraph;
        if ((cur == &other) && !ignoreSources)
            return true;
        if (cur->isDependentOn(other, false))
            return true;
    }
    return false;
}


bool ResourceGraphInfo::isDependentOn(ResourceGraphInfo & other, bool ignoreSources)
{
    //Cache the last query so that traversal doesn't convert a graph into a tree walk
    if ((cachedDependent.other == &other) && (cachedDependent.ignoreSources == ignoreSources) &&
        (cachedDependent.updateSequence == options->state.updateSequence))
        return cachedDependent.value;

    if (getDepth() <= other.getDepth())
        return false;

    cachedDependent.other = &other;
    cachedDependent.ignoreSources = ignoreSources;
    cachedDependent.updateSequence = options->state.updateSequence;
    cachedDependent.value = evalDependentOn(other, ignoreSources);
    return cachedDependent.value;
}


bool ResourceGraphInfo::isVeryCheap()
{
    if (sinks.ordinality() != 1)
        return false;

    IHqlExpression * sourceNode = sinks.item(0).sourceNode;
    if (isSimpleAggregateResult(sourceNode))
        return true;

//  Not sure about the following....
//  if (sourceNode->getOperator() == no_setresult)
//      return true;

    //Could be other examples...
    return false;
}


bool ResourceGraphInfo::mergeInSource(ResourceGraphInfo & other, const CResources & limit, bool isConditionalLink)
{
    bool mergeConditions = false;
    if (!isUnconditional)
    {
        //if it is conditional and it is very cheap then it is still more efficient to merge 
        //rather than read from a spill file.
        if (other.isUnconditional || !hasSameConditions(other))
        {
            if ((hasConditionSource || !isVeryCheap()) && (other.sinks.ordinality() != 1))
                return false;
            mergeConditions = true;
        }
    }

    if (isDependentOn(other, true))
        return false;

    if (!options->canSplit())
    {
        //Don't merge two graphs that will cause a splitter to be created
        //Either already used internally, or an output will be merged twice
        HqlExprArray mergeNodes;
        ForEachItemIn(idx, sources)
        {
            ResourceGraphLink & cur = sources.item(idx);
            if (cur.sourceGraph == &other)
            {
                IHqlExpression * sourceNode = cur.sourceNode->queryBody();
                ResourcerInfo * info = queryResourceInfo(sourceNode);
                if ((info->numInternalUses() != 0) || (mergeNodes.find(*sourceNode) != NotFound) || info->preventMerge())
                    return false;
                mergeNodes.append(*LINK(sourceNode));
            }
        }
    }

    if (options->checkResources() && !allocateResources(other.resources, limit))
        return false;

    mergeGraph(other, isConditionalLink, mergeConditions);
    return true;
}

void ResourceGraphInfo::mergeGraph(ResourceGraphInfo & other, bool isConditionalLink, bool mergeConditions)
{
#ifdef TRACE_RESOURCING
    DBGLOG("Merging%s source into%s sink", other.isUnconditional ? "" : " conditional", isUnconditional ? "" : " conditional");
    other.display();
    display();
    PrintLog("Merge %p into %p", &other, this);
#endif

    if (other.hasConditionSource)
        hasConditionSource = true;

    //Recalculate the dependents, because sources of the source merged in may no longer be indirect
    //although they may be via another path.  
    options->noteGraphsChanged();

    //If was very cheap and merged into an unconditional graph, make sure this is now tagged as
    //unconditional...
    if (other.isUnconditional)
        isUnconditional = true;

    //We need to stop spills being an arm of a conditional branch - otherwise they won't get executed.
    //so see if we have merged any conditional branches in
    if (isConditionalLink || other.mergedConditionSource)
        mergedConditionSource = true;

    if (mergeConditions)
    {
        //Replace conditions with those of parent.  Only called when a very simple graph is
        //merged in, so replace conditions instead of merging
        conditions.kill();
        ForEachItemIn(i, other.conditions)
            conditions.append(OLINK(other.conditions.item(i)));
    }
    
    //sources and sinks are updated elsewhere...
}


bool ResourceGraphInfo::mergeInSibling(ResourceGraphInfo & other, const CResources & limit)
{
    if ((!isUnconditional || !other.isUnconditional) && !hasSameConditions(other))
        return false;

    if (isDependentOn(other, false) || other.isDependentOn(*this, false))
        return false;

    if (options->checkResources() && !allocateResources(other.resources, limit))
        return false;

    mergeGraph(other, false, false);
    return true;
}


void ResourceGraphInfo::removeResources(const CResources & value)
{
    resources.sub(value);
}



//---------------------------------------------------------------------------

ResourcerInfo::ResourcerInfo(IHqlExpression * _original, CResourceOptions * _options) 
{ 
    original.set(_original); 
    numUses = 0;
    numExternalUses = 0;
    gatheredDependencies = false;
    containsActivity = false;
    isActivity = false;
    transformed = NULL;
    conditionSourceCount = 0;
    pathToExpr = PathUnknown;
    outputToUseForSpill = NULL;
    isAlreadyInScope = false;
    isSpillPoint = false;
    options = _options;
    balanced = true;
    currentSource = 0;
    linkedFromChild = false;
    neverSplit = false;
}

void ResourcerInfo::setConditionSource(IHqlExpression * condition, bool isFirst)            
{ 
    if (isFirst)
    {
        conditionSourceCount++; 
        graph->hasConditionSource = true;
    }
}

bool ResourcerInfo::addCondition(IHqlExpression * condition)
{
    conditions.append(*LINK(condition));
    return graph->addCondition(condition);
}

void ResourcerInfo::addSpillFlags(HqlExprArray & args, bool isRead)
{
    IHqlExpression * grouping = (IHqlExpression *)original->queryType()->queryGroupInfo();
    if (grouping)
        args.append(*createAttribute(groupedAtom));

    if (outputToUseForSpill)
    {
        assertex(isRead);
        if (outputToUseForSpill->hasProperty(__compressed__Atom))
            args.append(*createAttribute(__compressed__Atom));
    }
    else
    {
        args.append(*createAttribute(__compressed__Atom));
        args.append(*createAttribute(_spill_Atom));
        args.append(*createAttribute(_noReplicate_Atom));
        if (options->targetRoxie())
            args.append(*createAttribute(_noAccess_Atom));
    }

    if (isRead)
    {
        args.append(*createAttribute(_noVirtual_Atom));         // Don't interpret virtual fields as virtual...
        if (!original->isDataset() || hasSingleRow(original))
            args.append(*createAttribute(rowAtom));                 // add a flag so the selectnth[1] can be removed later...
    }
    else
    {
        unsigned numUses = numExternalUses;
        if (false) // options->cloneConditionals)
        {
            //Remove all the links from conditional graphs...
            ForEachItemIn(i1, graph->sinks)
            {
                ResourceGraphLink & cur = graph->sinks.item(i1);
                if ((cur.sourceNode == original) && (cur.linkKind == ConditionalLink || !cur.sinkGraph->isUnconditional))
                    numUses--;
            }
            numUses += calcNumConditionalUses();
        }
        args.append(*createAttribute(_tempCount_Atom, getSizetConstant(numUses)));
    }
}

bool ResourcerInfo::alwaysExpand()
{
    return (original->getOperator() == no_mapto);
}

static IHqlExpression * stripTrueFalse(IHqlExpression * expr)
{
    if (expr->queryName() == instanceAtom)
    {
        IHqlExpression * parent = expr->queryChild(2);
        if (parent)
            parent = stripTrueFalse(parent);
        return createAttribute(instanceAtom, LINK(expr->queryChild(0)), LINK(expr->queryChild(1)), parent);
    }
    else
    {
        IHqlExpression * parent = expr->queryChild(1);
        if (parent && parent->isAttribute())
            parent = stripTrueFalse(parent);
        return createAttribute(tempAtom, LINK(expr->queryChild(0)), parent);
    }
}

unsigned ResourcerInfo::calcNumConditionalUses()
{
    //for thor and hthor, where the conditional graph is cloned, the maximum number of times it can be read
    //is 1 for a shared conditional graph, or once for each combination of conditions it is used as the
    //input for.  However if it is used more than once in a single branch of a condition it needs to be counted
    //several times.
    //It is always better to overestimate than underestimate. (But even better to get it right.)
    HqlExprArray uniqueConditions;
    UnsignedArray uniqueCounts;
    ForEachItemIn(idx, conditions)
    {
        IHqlExpression & cur = conditions.item(idx);
        OwnedHqlExpr unique = stripTrueFalse(&cur);
        unsigned numOccurences = 0;
        ForEachItemIn(j, conditions)
            if (&conditions.item(j) == &cur)
                numOccurences++;

        unsigned match = uniqueConditions.find(*unique);
        if (match == NotFound)
        {
            uniqueConditions.append(*unique.getClear());
            uniqueCounts.append(numOccurences);
        }
        else
        {
            if (uniqueCounts.item(match) < numOccurences)
                uniqueCounts.replace(numOccurences, match);
        }
    }

    unsigned condUses = 0;
    ForEachItemIn(k, uniqueCounts)
        condUses += uniqueCounts.item(k);
    return condUses;
}


// Each aggregate has form.  Setresult(select(selectnth(aggregate...,1),field),name,seq)
IHqlExpression * ResourcerInfo::createAggregation(IHqlExpression * expr)
{
    LinkedHqlExpr transformed = expr;
    ForEachItemIn(idx, aggregates)
    {
        IHqlExpression & cur = aggregates.item(idx);
        IHqlExpression * row2ds = cur.queryChild(0);
        IHqlExpression * selectnth = row2ds->queryChild(0);
        IHqlExpression * aggregate = selectnth->queryChild(0);
        IHqlExpression * aggregateRecord = aggregate->queryChild(1);
        assertex(aggregate->getOperator() == no_newaggregate);
        HqlExprArray aggargs, setargs;
        //Through aggregate has form (dataset, record, transform, list of set results);
        aggargs.append(*LINK(transformed));
        aggargs.append(*LINK(aggregateRecord));
        IHqlExpression * mapped = replaceSelector(aggregate->queryChild(2), original, expr->queryNormalizedSelector());
        aggargs.append(*mapped);

        OwnedHqlExpr active = createDataset(no_anon, LINK(aggregateRecord), NULL);
        OwnedHqlExpr mappedSelect = replaceSelector(cur.queryChild(1), row2ds, active);
        setargs.append(*LINK(active));
        setargs.append(*LINK(mappedSelect));
        unwindChildren(setargs, &cur, 1);
        aggargs.append(*createValue(no_extractresult, makeVoidType(), setargs));
        transformed.setown(createDataset(no_throughaggregate, aggargs));
    }

    return transformed.getClear();
}

bool ResourcerInfo::useGraphResult()
{
    if (!options->useGraphResults)
        return false;

    if (linkedFromChild)
        return true;
    if (options->targetClusterType != HThorCluster)
        return false;
    return true;
}

bool ResourcerInfo::useGlobalResult()
{
    return (linkedFromChild && !useGraphResult());
}

IHqlExpression * ResourcerInfo::createSpillName()
{
    if (outputToUseForSpill)
        return LINK(outputToUseForSpill->queryChild(1));
    if (!spillName)
    {
        if (useGraphResult())
            spillName.setown(options->createSpillName(true));
        else if (useGlobalResult())
        {
            StringBuffer valueText;
            getUniqueId(valueText.append("spill"));
            spillName.setown(createConstant(valueText.str()));
        }
        else
            spillName.setown(options->createSpillName(false));
    }
    return LINK(spillName);
}


IHqlExpression * ResourcerInfo::createSpilledRead(IHqlExpression * spillReason)
{
    OwnedHqlExpr dataset;
    HqlExprArray args;

    IHqlExpression * record = original->queryRecord();
    bool loseDistribution = true;
    if (useGraphResult())
    {
        args.append(*LINK(record));
        args.append(*LINK(options->graphIdExpr));
        args.append(*createSpillName());
        if (isGrouped(original))
            args.append(*createAttribute(groupedAtom));
        if (!original->isDataset())
            args.append(*createAttribute(rowAtom));
        args.append(*createAttribute(_spill_Atom));
        IHqlExpression * recordCountAttr = queryRecordCountInfo(original);
        if (recordCountAttr)
            args.append(*LINK(recordCountAttr));
        if (options->targetThor() && original->isDataset() && !options->isChildQuery)
            args.append(*createAttribute(_distributed_Atom));
        dataset.setown(createDataset(no_getgraphresult, args));
    }
    else if (useGlobalResult())
    {
        args.append(*LINK(record));
        args.append(*createAttribute(nameAtom, createSpillName()));
        args.append(*createAttribute(sequenceAtom, getLocalSequenceNumber()));
        addSpillFlags(args, true);
        IHqlExpression * recordCountAttr = queryRecordCountInfo(original);
        if (recordCountAttr)
            args.append(*LINK(recordCountAttr));
        dataset.setown(createDataset(no_workunit_dataset, args));
    }
    else
    {
        if (spilledDataset)
        {
            args.append(*LINK(spilledDataset));
            args.append(*createSpillName());
        }
        else
        {
            args.append(*createSpillName());
            args.append(*LINK(record));
        }
        args.append(*createValue(no_thor));
        addSpillFlags(args, true);
        args.append(*createUniqueId());
        if (options->isChildQuery && options->targetRoxie())
        {
            args.append(*createAttribute(_colocal_Atom));
            args.append(*createLocalAttribute());
        }
        if (spillReason)
            args.append(*LINK(spillReason));

        if (spilledDataset)
            dataset.setown(createDataset(no_readspill, args));
        else
        {
            IHqlExpression * recordCountAttr = queryRecordCountInfo(original);
            if (recordCountAttr)
                args.append(*LINK(recordCountAttr));
            dataset.setown(createDataset(no_table, args));
        }

        loseDistribution = false;
    }

    dataset.setown(preserveTableInfo(dataset, original, loseDistribution, NULL));
    return wrapRowOwn(dataset.getClear());
}

IHqlExpression * ResourcerInfo::createSpilledWrite(IHqlExpression * transformed)
{
    assertex(!outputToUseForSpill);
    HqlExprArray args;

    if (useGraphResult())
    {
        assertex(options->graphIdExpr);
        args.append(*LINK(transformed));
        args.append(*LINK(options->graphIdExpr));
        args.append(*createSpillName());
        args.append(*createAttribute(_spill_Atom));
        return createValue(no_setgraphresult, makeVoidType(), args);
    }
    else if (useGlobalResult())
    {
        args.append(*LINK(transformed));
        args.append(*createAttribute(sequenceAtom, getLocalSequenceNumber()));
        args.append(*createAttribute(namedAtom, createSpillName()));
        addSpillFlags(args, false);
        return createValue(no_output, makeVoidType(), args);
    }
    else
    {
        if (options->createSpillAsDataset)
        {
            IHqlExpression * value = LINK(transformed);
            if (value->isDatarow())
                value = createDatasetFromRow(value);
            spilledDataset.setown(createDataset(no_commonspill, value));
            args.append(*LINK(spilledDataset));
        }
        else
            args.append(*LINK(transformed));

        args.append(*createSpillName());
        addSpillFlags(args, false);
        if (options->createSpillAsDataset)
            return createValue(no_writespill, makeVoidType(), args);

        return createValue(no_output, makeVoidType(), args);
    }
}


bool ResourcerInfo::okToSpillThrough()
{
    bool isGraphResult = useGraphResult();
    if (isGraphResult)
        return options->allowThroughResult;

    if (useGlobalResult())
        return false;

    return (options->allowThroughSpill && !options->createSpillAsDataset);
}

bool ResourcerInfo::spillSharesSplitter()
{
    if (outputToUseForSpill || useGraphResult() || useGlobalResult())
        return false;
    if (okToSpillThrough())
        return false;
    if (!isSplit() || !balanced)
        return false;
    return true;
}

IHqlExpression * ResourcerInfo::createSpiller(IHqlExpression * transformed, bool reuseSplitter)
{
    if (outputToUseForSpill)
        return LINK(transformed);

    if (!okToSpillThrough())
    {
        OwnedHqlExpr split;
        if (reuseSplitter)
        {
            assertex(transformed->getOperator() == no_split);
            split.set(transformed);
        }
        else
        {
            if (transformed->isDataset())
                split.setown(createDataset(no_split, LINK(transformed), createComma(createAttribute(balancedAtom), createUniqueId())));
            else
                split.setown(createRow(no_split, LINK(transformed), createComma(createAttribute(balancedAtom), createUniqueId())));
            split.setown(cloneInheritedAnnotations(original, split));
        }

        splitterOutput.setown(createSpilledWrite(split));
        return split.getClear();
    }

    HqlExprArray args;
    node_operator op;
    args.append(*LINK(transformed));
    if (useGraphResult())
    {
        op = no_spillgraphresult;
        args.append(*LINK(options->graphIdExpr));
        args.append(*createSpillName());
        args.append(*createAttribute(_spill_Atom));
    }
    else
    {
        op = no_spill;
        args.append(*createSpillName());
        addSpillFlags(args, false);
    }


    OwnedHqlExpr spill;
    if (original->isDatarow())
        spill.setown(createRow(op, args));
    else
        spill.setown(createDataset(op, args));
    return cloneInheritedAnnotations(original, spill);
}

IHqlExpression * ResourcerInfo::createSplitter(IHqlExpression * transformed)
{
    if (transformed->getOperator() == no_libraryscopeinstance)
        return LINK(transformed);

    IHqlExpression * attr = createUniqueId();
    if (balanced)
        attr = createComma(attr, createAttribute(balancedAtom));
    OwnedHqlExpr split;
    if (transformed->isDataset())
        split.setown(createDataset(no_split, LINK(transformed), attr));
    else
        split.setown(createRow(no_split, LINK(transformed), attr));
    return cloneInheritedAnnotations(original, split);
}

IHqlExpression * ResourcerInfo::createTransformedExpr(IHqlExpression * expr)
{
    LinkedHqlExpr transformed = expr;
    if (aggregates.ordinality())
        transformed.setown(createAggregation(transformed));

    if (spillSharesSplitter())
    {
        transformed.setown(createSplitter(transformed));

        if (isExternalSpill())
            transformed.setown(createSpiller(transformed, true));
    }
    else
    {
        if (isExternalSpill())
            transformed.setown(createSpiller(transformed, false));
        if (isSplit())
            transformed.setown(createSplitter(transformed));
        else if (isSpilledWrite())
            transformed.setown(createSpilledWrite(transformed));
    }

    return transformed.getClear();
}

bool ResourcerInfo::expandRatherThanSpill(bool noteOtherSpills)
{
    if (options->shareDontExpand)
        return expandRatherThanSplit();

    IHqlExpression * expr = original;
    if (!options->minimiseSpills || linkedFromChild)
        noteOtherSpills = false;

    if (noteOtherSpills)
    {
        ResourcerInfo * info = queryResourceInfo(expr);
        if (info && info->isSpilledWrite())
            return (info->transformed == NULL);
    }
    bool isFiltered = false;
    bool isProcessed = false;
    loop
    {
        ResourcerInfo * info = queryResourceInfo(expr);
        if (info && info->neverSplit)
            return true;

        node_operator op = expr->getOperator();
        switch (op)
        {
        case no_table:
            {
                //This is only executed for hthor/thor.  Roxie has used expandRatherThanSplit().
                //We need to balance the saving from reading reduced data in the other branches with the cost of
                //writing the spill file to disk.
                if (isFiltered && (numExternalUses >= options->filteredSpillThreshold))
                    return false;
                IHqlExpression * mode = expr->queryChild(2);
                switch (mode->getOperator())
                {
                case no_thor: case no_flat:
                    //MORE: The following is possibly better - but roxie should be able to read from non spill data files in child queries fine
                    //if ((options->targetClusterType == RoxieCluster) && linkedFromChild)) return false;
                    return true;
                default:
                    return false;
                }
            }
        case no_stepped:
            return true;
        case no_inlinetable:
            {
                IHqlExpression * transforms = expr->queryChild(0);
                //The inline table code means this should generate smaller code, and more efficient
                if (!isFiltered && !isProcessed && transforms->isConstant())
                    return true;

                if (transforms->numChildren() > MAX_INLINE_COMMON_COUNT)
                    return false;
                return true;
            }
        case no_getresult:
        case no_temptable:
        case no_rows:
        case no_xmlproject:
        case no_workunit_dataset:
            return !isProcessed && !isFiltered;
        case no_getgraphresult:
            return !expr->hasProperty(_streaming_Atom);         // we must not duplicate streaming inputs!
        case no_keyindex:
        case no_newkeyindex:
            if (!isFiltered)
                return true;
            return options->cloneFilteredIndex;
        case no_datasetfromrow:
            if (getNumActivityArguments(expr) == 0)
                return true;
            return false;
        case no_fail:
        case no_null:
            return !expr->isAction();
        case no_assertsorted:
        case no_sorted:
        case no_grouped:
        case no_distributed:
        case no_preservemeta:
        case no_nofold:
        case no_nohoist:
        case no_section:
        case no_sectioninput:
        case no_dataset_alias:
            expr = expr->queryChild(0);
            break;
        case no_newusertable:
        case no_limit:
        case no_keyedlimit:
            expr = expr->queryChild(0);
            isProcessed = true;
            break;
        case no_hqlproject:
            if (expr->hasProperty(_countProject_Atom) || expr->hasProperty(prefetchAtom))
                return false;
            expr = expr->queryChild(0);
            isProcessed = true;
            break;
            //MORE: Not so sure about all the following, include them so behaviour doesn't change 
        case no_compound_diskread:
        case no_compound_disknormalize:
        case no_compound_diskaggregate:
        case no_compound_diskcount:
        case no_compound_diskgroupaggregate:
        case no_compound_indexread:
        case no_compound_indexnormalize:
        case no_compound_indexaggregate:
        case no_compound_indexcount:
        case no_compound_indexgroupaggregate:
        case no_compound_childread:
        case no_compound_childnormalize:
        case no_compound_childaggregate:
        case no_compound_childcount:
        case no_compound_childgroupaggregate:
        case no_compound_selectnew:
        case no_compound_inline:
            expr = expr->queryChild(0);
            break;
        case no_filter:
            isFiltered = true;
            expr = expr->queryChild(0);
            break;
        case no_select:
            {
                if (options->targetClusterType == RoxieCluster)
                    return false;

                if (!expr->hasProperty(newAtom))
                    return true;
                expr = expr->queryChild(0);
                break;
            }
        default:
            return false;
        }

        //The following reduces the number of spills by taking into account other spills.
        if (noteOtherSpills)
        {
            ResourcerInfo * info = queryResourceInfo(expr);
            if (info)
            {
                if (info->isSpilledWrite())
                    return (info->transformed == NULL);
                if (info->numExternalUses)
                {
                    if (isFiltered && (numExternalUses >= options->filteredSpillThreshold))
                        return false;
                    return true;
                }
            }
        }
    }
}

bool ResourcerInfo::expandRatherThanSplit()
{
    //MORE: This doesn't really work - should do indexMatching first.
    //should only expand if one side that uses this is also filtered
    IHqlExpression * expr = original;
    loop
    {
        ResourcerInfo * info = queryResourceInfo(expr);
        if (info && info->neverSplit)
            return true;
        switch (expr->getOperator())
        {
        case no_keyindex:
        case no_newkeyindex:
        case no_rowset:
        case no_getgraphloopresultset:
            return true;
        case no_null:
            return !expr->isAction();
        case no_inlinetable:
            if (options->expandSingleConstRow && hasSingleRow(expr))
            {
                IHqlExpression * values = expr->queryChild(0);
                if (values->queryChild(0)->isConstant())
                    return true;
            }
            return false;
        case no_stepped:
        case no_rowsetrange:
        case no_rowsetindex:
            return true;
        case no_sorted:
        case no_grouped:
        case no_distributed:
        case no_preservemeta:
        case no_compound_diskread:
        case no_compound_disknormalize:
        case no_compound_diskaggregate:
        case no_compound_diskcount:
        case no_compound_diskgroupaggregate:
        case no_compound_indexread:
        case no_compound_indexnormalize:
        case no_compound_indexaggregate:
        case no_compound_indexcount:
        case no_compound_indexgroupaggregate:
        case no_compound_childread:
        case no_compound_childnormalize:
        case no_compound_childaggregate:
        case no_compound_childcount:
        case no_compound_childgroupaggregate:
        case no_compound_selectnew:
        case no_compound_inline:
        case no_section:
        case no_sectioninput:
        case no_dataset_alias:
            break;
        case no_select:
            if (options->targetClusterType == RoxieCluster)
                return false;
            if (!expr->hasProperty(newAtom))
            {
                if (!options->useLinkedRawIterator || !hasLinkCountedModifier(expr))
                    return false;
                return true;
            }
            break;
        case no_rows:
            //If executing in a child query then you'll have less thread contention if the iterator is duplicated
            //So should probably uncomment the following.
            //return true;
            return false;
        default:
            return false;
        }
        expr = expr->queryChild(0);
    }
}

bool neverCommonUp(IHqlExpression * expr)
{
    loop
    {
        node_operator op = expr->getOperator();
        switch (op)
        {
        case no_keyindex:
        case no_newkeyindex:
            return true;
        case no_filter:
            expr = expr->queryChild(0);
            break;
        default:
            return false;
        }
    }
}


bool ResourcerInfo::neverCommonUp()
{
    return ::neverCommonUp(original);
}

bool ResourcerInfo::isExternalSpill()
{
    if (expandRatherThanSpill(true) || (numInternalUses() == 0))
        return false;
    return (numExternalUses != 0);
}

bool ResourcerInfo::isSplit()
{ 
    return numSplitPaths() > 1; 
}

unsigned ResourcerInfo::numSplitPaths()
{
    unsigned internal = numInternalUses();
    if ((internal == 0) || !options->allowSplitBetweenSubGraphs)
        return internal;
    //MORE
    return internal;
}


bool ResourcerInfo::isSpilledWrite()
{
    if (numInternalUses() == 0)
        return true;
    return false;
}


IHqlExpression * ResourcerInfo::wrapRowOwn(IHqlExpression * expr)
{
    if (!original->isDataset())
        expr = createRow(no_selectnth, expr, getSizetConstant(1));
    return expr;
}

//---------------------------------------------------------------------------

EclResourcer::EclResourcer(IErrorReceiver * _errors, IConstWorkUnit * _wu, ClusterType _targetClusterType, unsigned _clusterSize, const HqlCppOptions & _translatorOptions)
{ 
    wu.set(_wu);
    errors = _errors;
    lockTransformMutex(); 
    targetClusterType = _targetClusterType; 
    clusterSize = _clusterSize ? _clusterSize : FIXED_CLUSTER_SIZE;
    insideNeverSplit = false;
    options.mangleSpillNameWithWuid = false;
    options.minimizeSpillSize = _translatorOptions.minimizeSpillSize;

    bool wuidIsConstant = (targetClusterType == RoxieCluster) || !wu->getCloneable();
    if (wuidIsConstant)
    {
        SCMStringBuffer wuNameText;
        wu->getWuid(wuNameText);
        options.filenameMangler.set(wuNameText.str());
    }

    unsigned totalMemory = _translatorOptions.resourceMaxMemory ? _translatorOptions.resourceMaxMemory : DEFAULT_TOTAL_MEMORY;
    unsigned maxSockets = _translatorOptions.resourceMaxSockets ? _translatorOptions.resourceMaxSockets : DEFAULT_MAX_SOCKETS;
    unsigned maxActivities = _translatorOptions.resourceMaxActivities ? _translatorOptions.resourceMaxActivities : DEFAULT_MAX_ACTIVITIES;
    unsigned maxHeavy = _translatorOptions.resourceMaxHeavy;
    unsigned maxDistribute = _translatorOptions.resourceMaxDistribute;

    resourceLimit = new CResources(0);
    resourceLimit->set(RESactivities, maxActivities);
    switch (targetClusterType)
    {
    case ThorCluster:
    case ThorLCRCluster:
        resourceLimit->set(RESheavy, maxHeavy).set(REShashdist, maxDistribute);
        resourceLimit->set(RESmastersocket, maxSockets).set(RESslavememory,totalMemory);
        resourceLimit->set(RESslavesocket, maxSockets).set(RESmastermemory, totalMemory);
        break;
    default:
        resourceLimit->set(RESheavy, 0xffffffff).set(REShashdist, 0xffffffff);
        resourceLimit->set(RESmastersocket, 0xffffffff).set(RESslavememory, 0xffffffff);
        resourceLimit->set(RESslavesocket, 0xffffffff).set(RESmastermemory, 0xffffffff);
        clusterSize = 1;
        break;
    }

    if (_translatorOptions.unlimitedResources)
    {
        resourceLimit->set(RESheavy, 0xffffffff).set(REShashdist, 0xffffffff);
        resourceLimit->set(RESmastersocket, 0xffffffff).set(RESslavememory,0xffffffff);
        resourceLimit->set(RESslavesocket, 0xffffffff).set(RESmastermemory,0xffffffff);
    }


    options.useMpForDistribute = (targetClusterType == ThorLCRCluster);
    
    if (_translatorOptions.hasResourceUseMpForDistribute)
        options.useMpForDistribute = _translatorOptions.resourceUseMpForDistribute;

    options.isChildQuery = false;
    options.targetClusterType = targetClusterType;
    options.filteredSpillThreshold = _translatorOptions.filteredReadSpillThreshold;
    options.allowThroughSpill = _translatorOptions.allowThroughSpill;
    options.allowThroughResult = (targetClusterType != RoxieCluster) && (targetClusterType != ThorLCRCluster);
    options.cloneFilteredIndex = (targetClusterType != RoxieCluster);
    options.spillSharedConditionals = (targetClusterType == RoxieCluster);
    options.shareDontExpand = (targetClusterType == RoxieCluster);
    options.graphIdExpr = NULL;
    //MORE The following doesn't always work - it gets sometimes confused about spill files - see latestheaderbuild for an example.
    //Try again once cloneConditionals is false for thor
    options.minimiseSpills = _translatorOptions.minimiseSpills;
    spillMultiCondition = _translatorOptions.spillMultiCondition;
    spotThroughAggregate = _translatorOptions.spotThroughAggregate && (targetClusterType != RoxieCluster) && (targetClusterType != ThorLCRCluster);
    options.noConditionalLinks = (targetClusterType == RoxieCluster);
    options.hoistResourced = _translatorOptions.hoistResourced;
    options.useGraphResults = false;        // modified by later call
    options.groupedChildIterators = _translatorOptions.groupedChildIterators;
    options.allowSplitBetweenSubGraphs = false;//(targetClusterType == RoxieCluster);
    options.supportsChildQueries = (targetClusterType != ThorCluster);
    options.clusterSize = clusterSize;
    options.preventKeyedSplit = _translatorOptions.preventKeyedSplit;
    options.preventSteppedSplit = _translatorOptions.preventSteppedSplit;
    options.minimizeSkewBeforeSpill = _translatorOptions.minimizeSkewBeforeSpill;
    options.expandSingleConstRow = true;
    options.createSpillAsDataset = _translatorOptions.optimizeSpillProject && (targetClusterType != HThorCluster);
    options.useLinkedRawIterator = _translatorOptions.useLinkedRawIterator;
    options.combineSiblings = _translatorOptions.combineSiblingGraphs && (targetClusterType != HThorCluster) && (targetClusterType != RoxieCluster);
    options.optimizeSharedInputs = _translatorOptions.optimizeSharedGraphInputs && options.combineSiblings;
}

EclResourcer::~EclResourcer()               
{ 
    delete resourceLimit;
    unlockTransformMutex(); 
}

void EclResourcer::setChildQuery(bool value) 
{ 
    options.isChildQuery = value; 
    if (value)
        options.createSpillAsDataset = false;
}

void EclResourcer::setNewChildQuery(IHqlExpression * graphIdExpr, unsigned numResults) 
{ 
    options.graphIdExpr = graphIdExpr; 
    options.nextResult = numResults;
}

void EclResourcer::changeGraph(IHqlExpression * expr, ResourceGraphInfo * newGraph)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    info->graph.set(newGraph);
    ForEachItemInRev(idx, links)
    {
        ResourceGraphLink & cur = links.item(idx);
        if (cur.sourceNode == expr)
            cur.changeSourceGraph(newGraph);
        else if (cur.sinkNode == expr)
            cur.changeSinkGraph(newGraph);
        assertex(cur.sinkGraph != cur.sourceGraph);
    }
}


ResourceGraphInfo * EclResourcer::createGraph()
{
    ResourceGraphInfo * graph = new ResourceGraphInfo(&options);
    graphs.append(*LINK(graph));
    //PrintLog("Create graph %p", graph);
    return graph;
}

void EclResourcer::connectGraphs(ResourceGraphInfo * sourceGraph, IHqlExpression * sourceNode, ResourceGraphInfo * sinkGraph, IHqlExpression * sinkNode, LinkKind kind)
{
    ResourceGraphLink * link = new ResourceGraphLink(sourceGraph, sourceNode, sinkGraph, sinkNode, kind);
    links.append(*link);
    if (sourceGraph)
        sourceGraph->sinks.append(*link);   
    if (sinkGraph)
        sinkGraph->sources.append(*link);
}


ResourcerInfo * EclResourcer::queryCreateResourceInfo(IHqlExpression * expr)
{
    IHqlExpression * body = expr->queryBody();
    ResourcerInfo * info = (ResourcerInfo *)body->queryTransformExtra();
    if (!info)
    {
        info = new ResourcerInfo(expr, &options);
        body->setTransformExtraOwned(info);
    }
    return info;
}


void EclResourcer::replaceGraphReferences(IHqlExpression * expr, ResourceGraphInfo * oldGraph, ResourceGraphInfo * newGraph)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info || !info->containsActivity)
        return;

    if (info->isActivity && info->graph != oldGraph)
        return;

    info->graph.set(newGraph);
    unsigned first = getFirstActivityArgument(expr);
    unsigned last = first + getNumActivityArguments(expr);
    for (unsigned idx=first; idx < last; idx++)
        replaceGraphReferences(expr->queryChild(idx), oldGraph, newGraph);
}


void EclResourcer::removeLink(ResourceGraphLink & link, bool keepExternalUses)
{
    ResourcerInfo * info = (ResourcerInfo *)queryResourceInfo(link.sourceNode);
    assertex(info && info->numExternalUses > 0);
    if (!keepExternalUses)
        info->numExternalUses--;
    if (link.sinkGraph)
        link.sinkGraph->sources.zap(link);
    link.sourceGraph->sinks.zap(link);
    links.zap(link);
}

void EclResourcer::replaceGraphReferences(ResourceGraphInfo * oldGraph, ResourceGraphInfo * newGraph)
{
    ForEachItemIn(idx1, oldGraph->sinks)
    {
        ResourceGraphLink & sink = oldGraph->sinks.item(idx1);
        replaceGraphReferences(sink.sourceNode, oldGraph, newGraph);
    }

    ForEachItemInRev(idx2, links)
    {
        ResourceGraphLink & cur = links.item(idx2);
        if (cur.sourceGraph == oldGraph)
        {
            if (cur.sinkGraph == newGraph)
                removeLink(cur, false);
            else
                cur.changeSourceGraph(newGraph);
        }
        else if (cur.sinkGraph == oldGraph)
        {
            if (cur.sourceGraph == newGraph)
                removeLink(cur, false);
            else
                cur.changeSinkGraph(newGraph);
        }
    }
}

//------------------------------------------------------------------------------------------
// PASS1: Gather information about splitter locations..
void EclResourcer::tagActiveCursors(HqlExprCopyArray & activeRows)
{
    ForEachItemIn(i, activeRows)
    {
        IHqlExpression & cur = activeRows.item(i);
        activeSelectors.append(cur);
        queryCreateResourceInfo(&cur)->isAlreadyInScope = true;
    }
}

inline bool projectSelectorDatasetToField(IHqlExpression * row)
{
    return ((row->getOperator() == no_selectnth) && getFieldCount(row->queryRecord()) > 1);
}


static HqlTransformerInfo eclHoistLocatorInfo("EclHoistLocator");
class EclHoistLocator : public NewHqlTransformer
{
public:
    EclHoistLocator(HqlExprCopyArray & _originalMatches, HqlExprArray & _matches, BoolArray & _alwaysHoistMatches) 
        : NewHqlTransformer(eclHoistLocatorInfo), originalMatched(_originalMatches), matched(_matches), alwaysHoistMatches(_alwaysHoistMatches)
    { 
    }

    void noteDataset(IHqlExpression * expr, IHqlExpression * hoisted, bool alwaysHoist)
    {
        unsigned match = originalMatched.find(*expr);
        if (match == NotFound)
        {
            if (!hoisted)
                hoisted = expr;

            originalMatched.append(*expr);
            matched.append(*LINK(hoisted));
            alwaysHoistMatches.append(alwaysHoist);
        }
        else if (alwaysHoist && !alwaysHoistMatches.item(match))
            alwaysHoistMatches.replace(true, match);
    }

    void noteScalar(IHqlExpression * expr, IHqlExpression * value)
    {
        if (!originalMatched.contains(*expr))
        {
            OwnedHqlExpr hoisted;
            if (value->getOperator() == no_select)
            {
                bool isNew;
                IHqlExpression * row = querySelectorDataset(value, isNew);
                if(isNew || row->isDatarow())
                {
                    if (projectSelectorDatasetToField(row))
                    {
                        IHqlExpression * ds = row->queryChild(0);

                        //Project down to a single field.so implicit fields can still be optimized
                        IHqlExpression * field = value->queryChild(1);
                        OwnedHqlExpr record = createRecord(field);
                        OwnedHqlExpr self = getSelf(record);
                        OwnedHqlExpr activeDs = createRow(no_activetable, LINK(ds->queryNormalizedSelector()));
                        OwnedHqlExpr selected = replaceSelector(value, row, activeDs);
                        OwnedHqlExpr assign = createAssign(createSelectExpr(LINK(self), LINK(field)), selected.getClear());
                        OwnedHqlExpr transform = createValue(no_newtransform, makeTransformType(record->getType()), LINK(assign));
                        OwnedHqlExpr projectedDs = createDataset(no_newusertable, LINK(ds), createComma(LINK(record), LINK(transform)));
                        hoisted.setown(replaceChild(row, 0, projectedDs));
                    }

                    if (!hoisted)
                        hoisted.set(row);
                }
            }
            else if (value->getOperator() == no_createset)
            {
                IHqlExpression * ds = value->queryChild(0);
                IHqlExpression * selected = value->queryChild(1);

                OwnedHqlExpr field;
                //Project down to a single field.so implicit fields can still be optimized
                if (selected->getOperator() == no_select)
                    field.set(selected->queryChild(1));
                else
                    field.setown(createField(valueAtom, selected->getType(), NULL));
                OwnedHqlExpr record = createRecord(field);
                OwnedHqlExpr self = getSelf(record);
                OwnedHqlExpr assign = createAssign(createSelectExpr(LINK(self), LINK(field)), LINK(selected));
                OwnedHqlExpr transform = createValue(no_newtransform, makeTransformType(record->getType()), LINK(assign));
                hoisted.setown(createDataset(no_newusertable, LINK(ds), createComma(LINK(record), LINK(transform))));
            }

            if (!hoisted)
            {
                OwnedHqlExpr field = createField(valueAtom, value->getType(), NULL);
                OwnedHqlExpr record = createRecord(field);
                OwnedHqlExpr self = getSelf(record);
                OwnedHqlExpr assign = createAssign(createSelectExpr(LINK(self), LINK(field)), LINK(value));
                OwnedHqlExpr transform = createValue(no_transform, makeTransformType(record->getType()), LINK(assign));
                hoisted.setown(createRow(no_createrow, LINK(transform)));
            }

            originalMatched.append(*expr);
            matched.append(*hoisted.getClear());
            alwaysHoistMatches.append(true);
        }
    }

protected:
    HqlExprCopyArray & originalMatched;
    HqlExprArray & matched;
    BoolArray & alwaysHoistMatches;
};



class EclChildSplitPointLocator : public EclHoistLocator
{
public:
    EclChildSplitPointLocator(IHqlExpression * _original, HqlExprCopyArray & _selectors, HqlExprCopyArray & _originalMatches, HqlExprArray & _matches, BoolArray & _alwaysHoistMatches, bool _groupedChildIterators, bool _supportsChildQueries) 
    : EclHoistLocator(_originalMatches, _matches, _alwaysHoistMatches), selectors(_selectors), groupedChildIterators(_groupedChildIterators), supportsChildQueries(_supportsChildQueries)
    { 
        original = _original;
        okToSelect = false; 
        gathered = false;
        conditionalDepth = 0;
        executedOnce = false;
        switch (original->getOperator())
        {
        case no_call:
        case no_externalcall:
        case no_libraryscopeinstance:
            okToSelect = true;
            break;
        }
    }

    void findSplitPoints(IHqlExpression * expr, unsigned from, unsigned to, bool _executedOnce)
    {
        for (unsigned i=from; i < to; i++)
        {
            IHqlExpression * cur = expr->queryChild(i);
            executedOnce = _executedOnce || cur->isAttribute();     // assume attributes are only executed once.
            findSplitPoints(cur);
        }
    }

protected:
    void findSplitPoints(IHqlExpression * expr)
    {
        //containsNonActiveDataset() would be nice - but that isn't percolated outside assigns etc.
        if (containsAnyDataset(expr) || containsMustHoist(expr))
        {
            if (!gathered)
            {
                gatherAmbiguousSelectors(original);
                gathered = true;
            }
            analyse(expr, 0);
        }
    }

    bool queryHoistDataset(IHqlExpression * ds)
    {
        bool alwaysHoist = true;
        if (executedOnce)
        {
            if (conditionalDepth != 0)
            {
                if (supportsChildQueries || canProcessInline(NULL, ds))
                    alwaysHoist = false;
            }
        }
        return alwaysHoist;
    }

    bool queryNoteDataset(IHqlExpression * ds)
    {
        bool alwaysHoist = queryHoistDataset(ds);
        //MORE: It should be possible to remove this condition, but it causes problems with resourcing hsss.xhql amongst others -> disable for the moment
        if (alwaysHoist)
            noteDataset(ds, ds, alwaysHoist);
        return alwaysHoist;
    }


    virtual void analyseExpr(IHqlExpression * expr)
    {
        if (alreadyVisited(expr))
            return;

        node_operator op = expr->getOperator();
        switch (op)
        {
        case no_select:
            if (expr->hasProperty(newAtom))
            {
                IHqlExpression * ds = expr->queryChild(0);
                if (isEvaluateable(ds))
                {
                    //MORE: Following isn't a very nice test - stops implicit denormalize getting messed up
                    if (expr->isDataset())
                        break;
                    
                    //Debtable.....
                    //Don't hoist counts on indexes or dataset - it may mean they are evaluated more frequently than need be.
                    //If dependencies and root graphs are handled correctly this could be deleted.
                    if (isCompoundAggregate(ds))
                        break;

                    if (!expr->isDatarow() && !expr->isDataset())
                    {
                        if (queryHoistDataset(ds))
                        {
                            noteScalar(expr, expr);
                            return;
                        }
                    }
                    else
                    {
                        if (queryNoteDataset(ds))
                            return;
                    }
                }
            }
            break;
        case no_createset:
            {
                IHqlExpression * ds = expr->queryChild(0);
                if (isEvaluateable(ds))
                {
                    if (queryHoistDataset(ds))
                    {
                        noteScalar(expr, expr);
//??                    queryNoteDataset(ds);
                        return;
                    }
                }
                break;
            }
        case no_assign:
            {
                IHqlExpression * rhs = expr->queryChild(1);
                //if rhs is a new, evaluatable, dataset then we want to add it
                if (rhs->isDataset() && isEvaluateable(rhs))
                {
                    if (queryNoteDataset(rhs))
                        return;
                }
                break;
            }
        case no_sizeof:
        case no_allnodes:
        case no_nohoist:
            return;
        case no_globalscope:
        case no_evalonce:
            if (expr->isDataset() || expr->isDatarow())
                noteDataset(expr, expr->queryChild(0), true);
            else
                noteScalar(expr, expr->queryChild(0));
            return;
        case no_thisnode:
            throwUnexpected();
        case no_getgraphresult:
            if (expr->hasProperty(_streaming_Atom) || expr->hasProperty(_distributed_Atom))
            {
                noteDataset(expr, expr, true);
                return;
            }
            break;
        case no_getgraphloopresult:
            noteDataset(expr, expr, true);
            return;
        case no_selectnth:
            if (expr->queryChild(1)->isConstant())
            {
                IHqlExpression * ds = expr->queryChild(0);
                switch (ds->getOperator())
                {
                case no_getgraphresult:
                    if (!expr->hasProperty(_streaming_Atom) && !expr->hasProperty(_distributed_Atom))
                        break;
                    //fallthrough
                case no_getgraphloopresult:
                    noteDataset(expr, expr, true);
                    return;
                }
            }
            break;
        }

        bool wasOkToSelect = okToSelect;
        if (expr->isDataset())
        {
            switch (expr->getOperator())
            {
            case no_compound_diskread:
            case no_compound_disknormalize:
            case no_compound_diskaggregate:
            case no_compound_diskcount:
            case no_compound_diskgroupaggregate:
            case no_compound_indexread:
            case no_compound_indexnormalize:
            case no_compound_indexaggregate:
            case no_compound_indexcount:
            case no_compound_indexgroupaggregate:
            case no_compound_childread:
            case no_compound_childnormalize:
            case no_compound_childaggregate:
            case no_compound_childcount:
            case no_compound_childgroupaggregate:
            case no_compound_selectnew:
            case no_compound_inline:
            case no_newkeyindex:
            case no_keyindex:
            case no_table:
                okToSelect = false;
                break;
            }

            if (okToSelect && isEvaluateable(expr))
            {
                if (queryNoteDataset(expr))
                    return;
            }
        }
        else
            okToSelect = true;

        switch (op)
        {
        case no_if:
            {
                IHqlExpression * cond = expr->queryChild(0);
//              bool condCanBeEvaluated = isEvaluateable(cond, true);
                analyseExpr(cond);
                if (expr->isDataset() || expr->isDatarow())
                    conditionalDepth++;
                doAnalyseChildren(expr, 1);
                if (expr->isDataset() || expr->isDatarow())
                    conditionalDepth--;
                break;
            }
        case no_mapto:
            {
                analyseExpr(expr->queryChild(0));
                if (expr->isDataset() || expr->isDatarow())
                    conditionalDepth++;
                analyseExpr(expr->queryChild(1));
                if (expr->isDataset() || expr->isDatarow())
                    conditionalDepth--;
                break;
            }
        default:
            NewHqlTransformer::analyseExpr(expr);
            break;
        }

        okToSelect = wasOkToSelect;
    }

    bool isCompoundAggregate(IHqlExpression * ds)
    {
        return false;
        //Generates worse code unless we take into account whether or not the newDisk operation flags are enabled.
        if (!isTrivialSelectN(ds))
            return false;
        IHqlExpression * agg = ds->queryChild(0);
        if (isSimpleCountAggregate(agg, true))
            return true;
        return false;
    }

    void gatherAmbiguousSelectors(IHqlExpression * expr)
    {
#ifndef ENSURE_SELSEQ_UID
        //Horrible code to try and cope with ambiguous left selectors.
        //o Tree is ambiguous so same child expression can occur in different contexts - so can't depend on the context it is found in to work out if can hoist
        //o If any selector that is hidden within child expressions matches one in scope then can't hoist it.
        //If the current expression creates a selector, then can't hoist anything that depends on it [only add to hidden if in selectors to reduce searching]
        //o Want to hoist as much as possible.
        if (selectors.empty())
            return;

        unsigned first = getFirstActivityArgument(expr);
        unsigned last = first + getNumActivityArguments(expr);
        unsigned max = expr->numChildren();
        unsigned i;
        HqlExprCopyArray hiddenSelectors;
        for (i = 0; i < first; i++)
            expr->queryChild(i)->gatherTablesUsed(&hiddenSelectors, NULL);
        for (i = last; i < max; i++)
            expr->queryChild(i)->gatherTablesUsed(&hiddenSelectors, NULL);

        ForEachItemIn(iSel, selectors)
        {
            IHqlExpression & cur = selectors.item(iSel);
            if (hiddenSelectors.contains(cur))
                ambiguousSelectors.append(cur);
        }

        switch (getChildDatasetType(expr))
        {
        case childdataset_datasetleft:
        case childdataset_left:
            {
                IHqlExpression * ds = expr->queryChild(0);
                IHqlExpression * selSeq = querySelSeq(expr);
                OwnedHqlExpr left = createSelector(no_left, ds, selSeq);
                if (selectors.contains(*left))
                    ambiguousSelectors.append(*left);
                break;
            }
        case childdataset_same_left_right:
        case childdataset_top_left_right:
        case childdataset_nway_left_right:
            {
                IHqlExpression * ds = expr->queryChild(0);
                IHqlExpression * selSeq = querySelSeq(expr);
                OwnedHqlExpr left = createSelector(no_left, ds, selSeq);
                OwnedHqlExpr right = createSelector(no_right, ds, selSeq);
                if (selectors.contains(*left))
                    ambiguousSelectors.append(*left);
                if (selectors.contains(*right))
                    ambiguousSelectors.append(*right);
                break;
            }
        case childdataset_leftright: 
            {
                IHqlExpression * leftDs = expr->queryChild(0);
                IHqlExpression * rightDs = expr->queryChild(1);
                IHqlExpression * selSeq = querySelSeq(expr);
                OwnedHqlExpr left = createSelector(no_left, leftDs, selSeq);
                OwnedHqlExpr right = createSelector(no_right, rightDs, selSeq);
                if (selectors.contains(*left))
                    ambiguousSelectors.append(*left);
                if (selectors.contains(*right))
                    ambiguousSelectors.append(*right);
                break;
            }
        }

#endif
    }

    bool isEvaluateable(IHqlExpression * ds, bool ignoreInline = false)
    {
        //Don't hoist an alias - it could create unnecessary duplicate spills - hoist its input
        if (ds->getOperator() == no_dataset_alias)
            return false;

        //Not allowed to hoist
        if (isContextDependent(ds, (conditionalDepth == 0), true))
            return false;

        //MORE: Needs more work for child queries - need a GroupedChildIterator activity
        if (isGrouped(ds) && selectors.ordinality() && !groupedChildIterators)
            return false;

        //Check datasets are available
        HqlExprCopyArray scopeUsed;
        ds->gatherTablesUsed(NULL, &scopeUsed);
        ForEachItemIn(i, scopeUsed)
        {
            IHqlExpression & cur = scopeUsed.item(i);
            if (!selectors.contains(cur))
                return false;

            if (ambiguousSelectors.contains(cur))
                return false;
        }

#ifdef MINIMAL_CHANGES
        if (isInlineTrivialDataset(ds) || (!ignoreInline && canProcessInline(NULL, ds)))
//      if (isInlineTrivialDataset(ds))// || (!ignoreInline && canProcessInline(NULL, ds)))
            return false;
#else
        //Not worth hoisting...
        if (isTrivialDataset(ds))
            return false;
#endif
        return true;
    }

protected:
    IHqlExpression * original;
    HqlExprCopyArray & selectors;
    HqlExprCopyArray ambiguousSelectors;
    unsigned conditionalDepth;
    bool okToSelect;
    bool gathered;
    bool groupedChildIterators;
    bool executedOnce;
    bool supportsChildQueries;
};



void EclResourcer::gatherChildSplitPoints(IHqlExpression * expr, BoolArray & alwaysHoistChild, ResourcerInfo * info, unsigned first, unsigned last)
{
    //NB: Don't call member functions to ensure correct nesting of transform mutexes.
    EclChildSplitPointLocator locator(expr, activeSelectors, info->originalChildDependents, info->childDependents, alwaysHoistChild, options.groupedChildIterators, options.supportsChildQueries);
    unsigned max = expr->numChildren();

    //If child queries are supported then don't hoist the expressions if they might only be evaluated once
    //because they may be conditional
    switch (expr->getOperator())
    {
    case no_setresult:
    case no_selectnth:
        //set results, only done once=>don't hoist conditionals
        locator.findSplitPoints(expr, last, max, true);
        return;
    }
    locator.findSplitPoints(expr, 0, first, true);          // IF() conditions only evaluated once... => don't force
    locator.findSplitPoints(expr, last, max, false);
}


class EclThisNodeLocator : public EclHoistLocator
{
public:
    EclThisNodeLocator(HqlExprCopyArray & _originalMatches, HqlExprArray & _matches, BoolArray & _alwaysHoistMatches) : EclHoistLocator(_originalMatches, _matches, _alwaysHoistMatches)
    { 
        allNodesDepth = 0;
    }

protected:
    virtual void analyseExpr(IHqlExpression * expr)
    {
        //NB: This doesn't really work for no_thisnode occurring in multiple contexts.  We should probably hoist it from everywhere if it is hoistable from anywhere,
        //    although theoretically that gives us problems with ambiguous selectors.
        if (alreadyVisited(expr) || !containsThisNode(expr))
            return;

        node_operator op = expr->getOperator();
        switch (op)
        {
        case no_allnodes:
            allNodesDepth++;
            NewHqlTransformer::analyseExpr(expr);
            allNodesDepth--;
            return;
        case no_thisnode:
            if (allNodesDepth == 0)
            {
                if (expr->isDataset() || expr->isDatarow())
                    noteDataset(expr, expr->queryChild(0), true);
                else
                    noteScalar(expr, expr->queryChild(0));
                return;
            }
            allNodesDepth--;
            NewHqlTransformer::analyseExpr(expr);
            allNodesDepth++;
            return;
        }
        NewHqlTransformer::analyseExpr(expr);
    }

protected:
    unsigned allNodesDepth;
};



bool EclResourcer::findSplitPoints(IHqlExpression * expr)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    bool savedInsideNeverSplit = insideNeverSplit;
    if (info && info->numUses)
    {
        if (insideNeverSplit)
            info->neverSplit = true;
        if (info->isAlreadyInScope && (info->numUses == 0) && expr->isDatarow())
        {
            // A row is already bound to a temporary
            info->isActivity = true;
            info->containsActivity = true;
            info->numUses++;

            //More: May need to force child activities to not be resourced (e.g., if somehow visited via another path)
            //info->preserve = true;
            return info->containsActivity;
        }

        if (info->isAlreadyInScope || info->isActivity || !info->containsActivity)
        {
            info->numUses++;
            return info->containsActivity;
        }
    }
    else
    {
        info = queryCreateResourceInfo(expr);
        info->numUses++;
        if (insideNeverSplit)
            info->neverSplit = true;

        bool isActivity = true;
        switch (expr->getOperator())
        {
        case no_select:
            //either a select from a setresult or use of a child-dataset
            if (expr->hasProperty(newAtom))
            {
                info->containsActivity = findSplitPoints(expr->queryChild(0));
                assertex(queryResourceInfo(expr->queryChild(0))->isActivity);
            }
            if (expr->isDataset() || expr->isDatarow())
            {
                info->isActivity = true;
                info->containsActivity = true;
            }
            return info->containsActivity;
        case no_mapto:
            throwUnexpected();
            info->containsActivity = findSplitPoints(expr->queryChild(1));
            return info->containsActivity;
        case no_activerow:
            info->isActivity = true;
            info->containsActivity = false;
            return false;
        case no_attr:
        case no_attr_expr:
        case no_attr_link:
        case no_rowset:                         // don't resource this as an activity
        case no_getgraphloopresultset:
            info->isActivity = false;
            info->containsActivity = false;
            return false;
        case no_datasetlist:
            isActivity = false;
            break;
        case no_rowsetrange:
            {
                //Don't resource this as an activity if it is a function of the input graph rows, 
                //however we do want to if it is coming from a dataset list.
                IHqlExpression * ds = expr->queryChild(0);
                //MORE: Should walk further down the tree to allow for nested rowsetranges etc.
                if (ds->getOperator() == no_rowset || ds->getOperator() == no_getgraphloopresultset)
                {
                    info->isActivity = false;
                    info->containsActivity = false;
                    return false;
                }
                isActivity = false;
                break;
            }
        case no_keyedlimit:
            if (options.preventKeyedSplit)
                insideNeverSplit = true;
            break;
        case no_filter:
            if (options.preventKeyedSplit && filterIsKeyed(expr))
                insideNeverSplit = true;
            break;
        case no_hqlproject:
        case no_newusertable:
        case no_aggregate:
        case no_newaggregate:
            if (options.preventKeyedSplit && expr->hasProperty(keyedAtom))
                insideNeverSplit = true;
            break;
        case no_stepped:
        case no_mergejoin:
        case no_nwayjoin:
            if (options.preventSteppedSplit)
                insideNeverSplit = true;
            break;
        case no_compound_diskread:
        case no_compound_disknormalize:
        case no_compound_diskaggregate:
        case no_compound_diskcount:
        case no_compound_diskgroupaggregate:
        case no_compound_indexread:
        case no_compound_indexnormalize:
        case no_compound_indexaggregate:
        case no_compound_indexcount:
        case no_compound_indexgroupaggregate:
        case no_compound_childread:
        case no_compound_childnormalize:
        case no_compound_childaggregate:
        case no_compound_childcount:
        case no_compound_childgroupaggregate:
        case no_compound_selectnew:
        case no_compound_inline:
            insideNeverSplit = true;
            break;
        }

        ITypeInfo * type = expr->queryType();
        if (!type || type->isScalar())
        {
            insideNeverSplit = savedInsideNeverSplit;
            return false;
        }

        info->isActivity = isActivity;
        info->containsActivity = true;
    }

    unsigned first = getFirstActivityArgument(expr);
    unsigned last = first + getNumActivityArguments(expr);

    if (options.hoistResourced)
    {
        BoolArray alwaysHoistChild;
        switch (expr->getOperator())
        {
        case no_allnodes:
            {
                //MORE: This needs to recursively walk and lift any contained no_selfnode, but don't go past another nested no_allnodes;
                EclThisNodeLocator locator(info->originalChildDependents, info->childDependents, alwaysHoistChild);
                locator.analyse(expr->queryChild(0), 0);
                break;
            }
        default:
            {
                for (unsigned idx=first; idx < last; idx++)
                {
                    IHqlExpression * cur = expr->queryChild(idx);
                    findSplitPoints(cur);
                }
                insideNeverSplit = savedInsideNeverSplit;
                gatherChildSplitPoints(expr, alwaysHoistChild, info, first, last);
                break;
            }
        }

        insideNeverSplit = false;
        ForEachItemIn(i2, info->childDependents)
        {
            IHqlExpression & cur = info->childDependents.item(i2);
            if (alwaysHoistChild.item(i2))
                findSplitPoints(&cur);
            else
                conditionalChildren.append(cur);
        }
    }
    else
    {
        for (unsigned idx=first; idx < last; idx++)
            findSplitPoints(expr->queryChild(idx));
    }

    insideNeverSplit = savedInsideNeverSplit;
    return info->containsActivity;
}


void EclResourcer::findSplitPoints(HqlExprArray & exprs)
{
    ForEachItemIn(idx, exprs)
        findSplitPoints(&exprs.item(idx));
    extendSplitPoints();
}

void EclResourcer::extendSplitPoints()
{
    for (unsigned i=0; i < conditionalChildren.ordinality(); i++)
    {
        IHqlExpression & cur = conditionalChildren.item(i);
        if (isWorthForcingHoist(&cur))
            findSplitPoints(&cur);
    }
}

//------------------------------------------------------------------------------------------
// PASS2: Actually create the subgraphs based on splitters.

void EclResourcer::createInitialGraph(IHqlExpression * expr, IHqlExpression * owner, ResourceGraphInfo * ownerGraph, LinkKind linkKind, bool forceNewGraph)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info || !info->containsActivity)
        return;

    LinkKind childLinkKind = UnconditionalLink;
    Linked<ResourceGraphInfo> thisGraph = ownerGraph;
    bool forceNewChildGraph = false; 
    if (info->isActivity)
    {
        //Need to ensure no_libraryselects are not separated from the no_libraryscopeinstance
        //so ensure they are placed in the same graph.
        node_operator op = expr->getOperator();
        if (op == no_libraryselect)
        {
            ResourcerInfo * moduleInfo = queryResourceInfo(expr->queryChild(1));
            if (!info->graph && moduleInfo->graph)
                info->graph.set(moduleInfo->graph);
        }

        if (info->graph)
        {
            connectGraphs(info->graph, expr, ownerGraph, owner, linkKind);
            info->numExternalUses++;
            return;
        }

        unsigned numUses = info->numUses;
        switch (op)
        {
        case no_libraryscopeinstance:
            numUses = 1;
            break;
        case no_libraryselect:
            forceNewGraph = true;
            break;
        }

        if (!ownerGraph || numUses > 1 || (linkKind != UnconditionalLink) || forceNewGraph)
        {
            thisGraph.setown(createGraph());
            connectGraphs(thisGraph, expr, ownerGraph, owner, linkKind);
            info->numExternalUses++;
        }
        info->graph.set(thisGraph);

        switch (expr->getOperator())
        {
        case no_compound:
            //NB: First argument is forced into a separate graph
            createInitialGraph(expr->queryChild(0), expr, NULL, UnconditionalLink, true);
            createInitialGraph(expr->queryChild(1), expr, thisGraph, UnconditionalLink, false);
            return;
        case no_executewhen:
            {
                bool newGraph = expr->isAction() && (options.targetClusterType == HThorCluster);
                createInitialGraph(expr->queryChild(0), expr, thisGraph, UnconditionalLink, newGraph);
                createInitialGraph(expr->queryChild(1), expr, thisGraph, UnconditionalLink, true);
                return;
            }
        case no_keyindex:
        case no_newkeyindex:
            return;
        case no_parallel:
            {
                ForEachChild(i, expr)
                    createInitialGraph(expr->queryChild(i), expr, thisGraph, UnconditionalLink, true);
                return;
            }
        case no_if:
            //conditional nodes, the child branches are marked as conditional
            childLinkKind = UnconditionalLink;
            thisGraph->mergedConditionSource = true;
            if (!options.noConditionalLinks || expr->isAction())
                forceNewChildGraph = true;
            break;
//      case no_nonempty:
        case no_sequential:
            {
                unsigned first = getFirstActivityArgument(expr);
                unsigned last = first + getNumActivityArguments(expr);
                createInitialGraph(expr->queryChild(first), expr, thisGraph, SequenceLink, true);
                for (unsigned idx = first+1; idx < last; idx++)
                    createInitialGraph(expr->queryChild(idx), expr, thisGraph, SequenceLink, true);
                return;
            }
        case no_case:
        case no_map:
            {
                throwUnexpected();
            }
        case no_output:
            {
                //Tag the inputs to an output statement, so that if a spill was going to occur we read
                //from the output file instead of spilling.
                //Needs the grouping to be saved in the same way.  Could cope with compressed matching, but not
                //much point - since fairly unlikely.
                IHqlExpression * filename = expr->queryChild(1);
                if (filename && (filename->getOperator() == no_constant) && !expr->hasProperty(xmlAtom) && !expr->hasProperty(csvAtom))
                {
                    IHqlExpression * dataset = expr->queryChild(0);
                    if (expr->hasProperty(groupedAtom) == (dataset->queryType()->queryGroupInfo() != NULL))
                    {
                        StringBuffer filenameText;
                        filename->queryValue()->getStringValue(filenameText);
                        ResourcerInfo * childInfo = queryResourceInfo(dataset);
                        if (!childInfo->linkedFromChild && !isUpdatedConditionally(expr))
                            childInfo->outputToUseForSpill = expr;
                    }
                }
                if (isUpdatedConditionally(expr))
                    thisGraph->mergedConditionSource = true;
                break;
            }
        case no_buildindex:
            if (isUpdatedConditionally(expr))
                thisGraph->mergedConditionSource = true;
            break;
        }
    }

    unsigned first = getFirstActivityArgument(expr);
    unsigned last = first + getNumActivityArguments(expr);
    for (unsigned idx = first; idx < last; idx++)
        createInitialGraph(expr->queryChild(idx), expr, thisGraph, childLinkKind, forceNewChildGraph);

    ForEachItemIn(i2, info->childDependents)
    {
        IHqlExpression & cur = info->childDependents.item(i2);
        if (isResourcedActivity(&cur))
            createInitialGraph(&cur, expr, thisGraph, SequenceLink, true);
    }
}


void EclResourcer::createInitialGraphs(HqlExprArray & exprs)
{
    ForEachItemIn(idx, exprs)
        createInitialGraph(&exprs.item(idx), NULL, NULL, UnconditionalLink, false);
}

void EclResourcer::createInitialRemoteGraph(IHqlExpression * expr, IHqlExpression * owner, ResourceGraphInfo * ownerGraph, bool forceNewGraph)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info || !info->containsActivity)
        return;

    Linked<ResourceGraphInfo> thisGraph = ownerGraph;
    if (info->isActivity)
    {
        if (info->graph)
        {
            connectGraphs(info->graph, expr, ownerGraph, owner, UnconditionalLink);
            info->numExternalUses++;
            return;
        }

        if (!ownerGraph || forceNewGraph)
        {
            thisGraph.setown(createGraph());
            connectGraphs(thisGraph, expr, ownerGraph, owner, UnconditionalLink);
            info->numExternalUses++;
        }
        info->graph.set(thisGraph);

        switch (expr->getOperator())
        {
        case no_compound:
            createInitialRemoteGraph(expr->queryChild(0), expr, NULL, true);
            createInitialRemoteGraph(expr->queryChild(1), expr, thisGraph, false);
            return;
        case no_executewhen:
            createInitialRemoteGraph(expr->queryChild(0), expr, thisGraph, false);
            createInitialRemoteGraph(expr->queryChild(1), expr, thisGraph, true);
            return;
        }
    }

    unsigned first = getFirstActivityArgument(expr);
    unsigned last = first + getNumActivityArguments(expr);
    for (unsigned idx = first; idx < last; idx++)
        createInitialRemoteGraph(expr->queryChild(idx), expr, thisGraph, false);
}


void EclResourcer::createInitialRemoteGraphs(HqlExprArray & exprs)
{
    ForEachItemIn(idx, exprs)
        createInitialRemoteGraph(&exprs.item(idx), NULL, NULL, false);
}

//------------------------------------------------------------------------------------------
// PASS3: Tag graphs/links that are conditional or unconditional

void EclResourcer::markChildDependentsAsUnconditional(ResourcerInfo * info, IHqlExpression * condition)
{
    if (options.hoistResourced)
    {
        ForEachItemIn(i2, info->childDependents)
        {
            IHqlExpression & cur = info->childDependents.item(i2);
            if (isResourcedActivity(&cur))
                markAsUnconditional(&cur, NULL, condition);
        }
    }
}

void EclResourcer::markAsUnconditional(IHqlExpression * expr, ResourceGraphInfo * ownerGraph, IHqlExpression * condition)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info || !info->containsActivity)
        return;

    if (!info->isActivity)
    {
        unsigned first = getFirstActivityArgument(expr);
        unsigned last = first + getNumActivityArguments(expr);
        for (unsigned idx=first; idx < last; idx++)
            markAsUnconditional(expr->queryChild(idx), ownerGraph, condition);
        return;
    }

    if (condition)
        if (info->addCondition(condition))
            condition = NULL;

    if (info->pathToExpr == ResourcerInfo::PathUnconditional)
        return;

    if ((info->pathToExpr == ResourcerInfo::PathConditional) && condition)
    {
        if (targetClusterType == RoxieCluster)
        {
            if (spillMultiCondition)
            {
                if (info->graph != ownerGraph)
                    info->graph->isUnconditional = true;
            }
            return;
        }
        else
        {
            if (info->graph != ownerGraph)
                return;
        }
    }

    bool wasConditional = (info->pathToExpr == ResourcerInfo::PathConditional);
    if (!condition)
    {
        info->pathToExpr = ResourcerInfo::PathUnconditional;
        if (info->graph != ownerGraph)
            info->graph->isUnconditional = true;
    }
    else
        info->pathToExpr = ResourcerInfo::PathConditional;

    node_operator op = expr->getOperator();
    switch (op)
    {
    case no_if:
        if (options.noConditionalLinks)
            break;
        if (condition)
            markCondition(expr, condition, wasConditional);
        else
        {
            //This list is processed in a second phase.
            if (rootConditions.find(*expr) == NotFound)
                rootConditions.append(*LINK(expr));
        }
        markChildDependentsAsUnconditional(info, condition);
        return;
    case no_sequential:
//  case no_nonempty:
        if (!options.isChildQuery)
        {
            unsigned first = getFirstActivityArgument(expr);
            unsigned last = first + getNumActivityArguments(expr);
            IHqlExpression * child0 = expr->queryChild(0);
            markAsUnconditional(child0, info->graph, condition);
            queryResourceInfo(child0)->graph->hasConditionSource = true;        // force it to generate even if contains something very simple e.g., null action
            for (unsigned idx = first+1; idx < last; idx++)
            {
                OwnedHqlExpr tag = createAttribute(instanceAtom, LINK(expr), getSizetConstant(idx), LINK(condition));
                IHqlExpression * child = expr->queryChild(idx);
                markAsUnconditional(child, queryResourceInfo(child)->graph, tag);

                queryResourceInfo(child)->setConditionSource(tag, !wasConditional);
            }
            markChildDependentsAsUnconditional(info, condition);
            return;
        }
        break;

    case no_case:
    case no_map:
        UNIMPLEMENTED;
    }

    unsigned first = getFirstActivityArgument(expr);
    unsigned last = first + getNumActivityArguments(expr);
    for (unsigned idx=first; idx < last; idx++)
        markAsUnconditional(expr->queryChild(idx), info->graph, condition);

    markChildDependentsAsUnconditional(info, condition);
}


void EclResourcer::markConditionBranch(unsigned childIndex, IHqlExpression * expr, IHqlExpression * condition, bool wasConditional)
{
    IHqlExpression * child = expr->queryChild(childIndex);
    if (child)
    {
        OwnedHqlExpr tag = createAttribute(((childIndex==1) ? trueAtom : falseAtom), LINK(expr), LINK(condition));
        markAsUnconditional(child, queryResourceInfo(child)->graph, tag);

        queryResourceInfo(child)->setConditionSource(tag, !wasConditional);
    }
}


void EclResourcer::markCondition(IHqlExpression * expr, IHqlExpression * condition, bool wasConditional)
{
    markConditionBranch(1, expr, condition, wasConditional);
    markConditionBranch(2, expr, condition, wasConditional);
}

void EclResourcer::markConditions(HqlExprArray & exprs)
{
    ForEachItemIn(idx, exprs)
        markAsUnconditional(&exprs.item(idx), NULL, NULL);

    ForEachItemIn(idx2, rootConditions)
        markCondition(&rootConditions.item(idx2), NULL, false);
}



//------------------------------------------------------------------------------------------
// PASS4: Split subgraphs based on resource requirements for activities
//This will need to be improved if we allow backtracking to get the best combination of activities to fit in the subgraph

void EclResourcer::createResourceSplit(IHqlExpression * expr, IHqlExpression * owner, ResourceGraphInfo * ownerNewGraph, ResourceGraphInfo * originalGraph)
{
    ResourcerInfo * info = queryResourceInfo(expr);

    info->graph.setown(createGraph());
    info->graph->isUnconditional = originalGraph->isUnconditional;
    changeGraph(expr, info->graph);
    connectGraphs(info->graph, expr, ownerNewGraph, owner, UnconditionalLink);
    info->numExternalUses++;
}



void EclResourcer::getResources(IHqlExpression * expr, CResources & exprResources)
{
    ::getResources(expr, exprResources, options);
}


bool EclResourcer::calculateResourceSpillPoints(IHqlExpression * expr, ResourceGraphInfo * graph, CResources & resourcesSoFar, bool hasGoodSpillPoint, bool canSpill)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info || !info->containsActivity)
        return true;

    if (!info->isActivity)
    {
        unsigned first = getFirstActivityArgument(expr);
        unsigned last = first + getNumActivityArguments(expr);
        if (last - first == 1)
            return calculateResourceSpillPoints(expr->queryChild(first), graph, resourcesSoFar, hasGoodSpillPoint, canSpill);
        for (unsigned idx = first; idx < last; idx++)
            calculateResourceSpillPoints(expr->queryChild(idx), graph, resourcesSoFar, false, canSpill);
        return true;
    }

    if (info->graph != graph)
        return true;

    CResources exprResources(clusterSize);
    getResources(expr, exprResources);

    info->isSpillPoint = false;
    Owned<CResources> curResources = LINK(&resourcesSoFar);
    if (resourcesSoFar.addExceeds(exprResources, *resourceLimit))
    {
        if (hasGoodSpillPoint)
            return false;
        info->isSpillPoint = true;
        spilled = true;
        curResources.setown(new CResources(clusterSize));
        if (exprResources.exceeds(*resourceLimit))
            throwError2(HQLERR_CannotResourceActivity, getOpString(expr->getOperator()), clusterSize);
    }

    if (options.minimizeSkewBeforeSpill)
    {
        if (canSpill && heavyweightAndReducesSizeOrSkew(expr))
        {
            //if the input activity is going to cause us to run out of resources, then it is going to be better to split here than anywhere else
            //this code may conceivably cause extra spills far away because the hash distributes are moved.
            IHqlExpression * childExpr = expr->queryChild(0);
            ResourcerInfo * childInfo = queryResourceInfo(childExpr);

            if (childInfo->graph == graph)
            {
                CResources childResources(clusterSize);
                getResources(childExpr, childResources);
                childResources.add(exprResources);
                if (curResources->addExceeds(childResources, *resourceLimit))
                {
                    info->isSpillPoint = true;
                    spilled = true;
                    calculateResourceSpillPoints(childExpr, graph, exprResources, false, true);
                    return true;
                }
            }
            //otherwise continue as normal.
        }
    }

    curResources->add(exprResources);

    unsigned first = getFirstActivityArgument(expr);
    unsigned last = first + getNumActivityArguments(expr);
    if (hasGoodSpillPoint)
    {
        if (exprResources.resource[RESheavy] || exprResources.resource[REShashdist] || last-first != 1)
            hasGoodSpillPoint = false;
    }
    else if (!info->isSpillPoint && canSpill)
    {
        if (lightweightAndReducesDatasetSize(expr) || queryHint(expr, spillAtom))
        {
            CResources savedResources(*curResources);
            if (!calculateResourceSpillPoints(expr->queryChild(0), graph, *curResources, true, true))
            {
                curResources->set(savedResources);
                info->isSpillPoint = true;
                spilled = true;
                calculateResourceSpillPoints(expr->queryChild(0), graph, exprResources, false, true);
            }
            return true;
        }
    }

    if (expr->getOperator() == no_if)
    {
        //For conditions, spill on intersection of resources used, not union.
        CResources savedResources(*curResources);
        if (!calculateResourceSpillPoints(expr->queryChild(1), graph, *curResources, hasGoodSpillPoint, true))
            return false;   
        if (expr->queryChild(2))
        {
            if (!calculateResourceSpillPoints(expr->queryChild(2), graph, savedResources, hasGoodSpillPoint, true))
                return false;
            curResources->maximize(savedResources);
        }
    }
    else
    {
        for (unsigned idx = first; idx < last; idx++)
            if (!calculateResourceSpillPoints(expr->queryChild(idx), graph, *curResources, hasGoodSpillPoint, true))
                return false;
    }
    return true;
}

void EclResourcer::insertResourceSpillPoints(IHqlExpression * expr, IHqlExpression * owner, ResourceGraphInfo * ownerOriginalGraph, ResourceGraphInfo * ownerNewGraph)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info || !info->containsActivity)
        return;

    if (!info->isActivity)
    {
        unsigned first = getFirstActivityArgument(expr);
        unsigned last = first + getNumActivityArguments(expr);
        for (unsigned idx = first; idx < last; idx++)
            insertResourceSpillPoints(expr->queryChild(idx), expr, ownerOriginalGraph, ownerNewGraph);
        return;
    }

    ResourceGraphInfo * originalGraph = info->graph;    //NB: Graph will never cease to exist, so don't need to link.
    if (originalGraph != ownerOriginalGraph)
        return;

    if (info->isSpillPoint)
        createResourceSplit(expr, owner, ownerNewGraph, originalGraph);
    else if (info->graph != ownerNewGraph)
        changeGraph(expr, ownerNewGraph);

    CResources exprResources(clusterSize);
    getResources(expr, exprResources);

    bool ok = info->graph->allocateResources(exprResources, *resourceLimit);
    assertex(ok);

    if (expr->getOperator() == no_if)
    {
        CResources savedResources(info->graph->resources);
        insertResourceSpillPoints(expr->queryChild(1), expr, originalGraph, info->graph);
        if (expr->queryChild(2))
        {
            CResources branchResources(info->graph->resources);
            info->graph->resources.set(savedResources);
            insertResourceSpillPoints(expr->queryChild(2), expr, originalGraph, info->graph);
            info->graph->resources.maximize(branchResources);
        }
    }
    else
    {
        unsigned first = getFirstActivityArgument(expr);
        unsigned last = first + getNumActivityArguments(expr);
        for (unsigned idx = first; idx < last; idx++)
            insertResourceSpillPoints(expr->queryChild(idx), expr, originalGraph, info->graph);
    }
}


void EclResourcer::resourceSubGraph(ResourceGraphInfo * graph)
{
    if (graph->beenResourced)
        return;
    graph->beenResourced = true;
    ForEachItemIn(idx, graph->sources)
        resourceSubGraph(graph->sources.item(idx).sourceGraph);

    IHqlExpression * sourceNode = graph->sinks.item(0).sourceNode->queryBody();
#ifdef _DEBUG
    //Sanity check, ensure there is only a single sink for this graph.  
    //However because libraryselects are tightly bound to their library instance there may be multiple library selects.  
    //They won't affect the resourcing though, since they'll plug into the same library instance, and the selects use no resources.
    ForEachItemIn(idx2, graph->sinks)
    {
        IHqlExpression * thisSink = graph->sinks.item(idx2).sourceNode->queryBody();
        if (thisSink->getOperator() != no_libraryselect)
            assertex(thisSink == sourceNode);
    }
#endif
    spilled = false;
    CResources resources(clusterSize);
    calculateResourceSpillPoints(sourceNode, graph, resources, false, false);
    if (spilled)
        insertResourceSpillPoints(sourceNode, NULL, graph, graph);
    else
        graph->resources.set(resources);
}

void EclResourcer::resourceSubGraphs(HqlExprArray & exprs)
{
    ForEachItemIn(idx, graphs)
        resourceSubGraph(&graphs.item(idx));
}


//------------------------------------------------------------------------------------------
// PASS5: Link subrgaphs with dependency information so they don't get merged by accident.

void EclResourcer::addDependencySource(IHqlExpression * search, ResourceGraphInfo * curGraph, IHqlExpression * expr)
{
    //MORE: Should we check this doesn't already exist?
    dependencySource.search.append(*LINK(search));
    dependencySource.graphs.append(*LINK(curGraph));
    dependencySource.exprs.append(*LINK(expr));
}

void EclResourcer::addDependencyUse(IHqlExpression * search, ResourceGraphInfo * curGraph, IHqlExpression * expr)
{
    unsigned index = dependencySource.search.find(*search);
    if (index != NotFound)
    {
        if (&dependencySource.graphs.item(index) == curGraph)
        {
            //Don't give a warning if get/set is within the same activity (e.g., within a local())
            if (&dependencySource.exprs.item(index) != expr)
            //errors->reportWarning(HQLWRN_RecursiveDependendencies, HQLWRN_RecursiveDependendencies_Text, *codeGeneratorAtom, 0, 0, 0);
                errors->reportError(HQLWRN_RecursiveDependendencies, HQLWRN_RecursiveDependendencies_Text, *codeGeneratorAtom, 0, 0, 0);
        }
        else
        {
            ResourceGraphLink * link = new ResourceGraphDependencyLink(&dependencySource.graphs.item(index), &dependencySource.exprs.item(index), curGraph, expr);
            curGraph->dependsOn.append(*link);
            links.append(*link);
        }
    }
}


void EclResourcer::addRefExprDependency(IHqlExpression * expr, ResourceGraphInfo * curGraph, IHqlExpression * activityExpr)
{
    IHqlExpression * filename = queryTableFilename(expr);
    if (filename)
    {
        OwnedHqlExpr value = createAttribute(fileAtom, getNormalizedFilename(filename));
        addDependencySource(value, curGraph, activityExpr);
    }
}

bool EclResourcer::addExprDependency(IHqlExpression * expr, ResourceGraphInfo * curGraph, IHqlExpression * activityExpr)
{
    switch (expr->getOperator())
    {
    case no_buildindex:
    case no_output:
        {
            IHqlExpression * filename = queryRealChild(expr, 1);
            if (filename)
            {
                switch (filename->getOperator())
                {
                case no_pipe:
//                  allWritten = true;
                    break;
                default:
                    OwnedHqlExpr value = createAttribute(fileAtom, getNormalizedFilename(filename));
                    addDependencySource(value, curGraph, activityExpr);
                    break;
                }
            }
            else
            {
                IHqlExpression * seq = querySequence(expr);
                assertex(seq && seq->queryValue());
                IHqlExpression * name = queryResultName(expr);
                OwnedHqlExpr value = createAttribute(resultAtom, LINK(seq), LINK(name));
                addDependencySource(value, curGraph, activityExpr);
            }
            return true;
        }
    case no_keydiff:
        {
            addRefExprDependency(expr->queryChild(0), curGraph, activityExpr);
            addRefExprDependency(expr->queryChild(1), curGraph, activityExpr);
            OwnedHqlExpr value = createAttribute(fileAtom, getNormalizedFilename(expr->queryChild(2)));
            addDependencySource(value, curGraph, activityExpr);
            return true;
        }
    case no_keypatch:
        {
            addRefExprDependency(expr->queryChild(0), curGraph, activityExpr);
            OwnedHqlExpr patchName = createAttribute(fileAtom, getNormalizedFilename(expr->queryChild(1)));
            addDependencyUse(patchName, curGraph, activityExpr);
            OwnedHqlExpr value = createAttribute(fileAtom, getNormalizedFilename(expr->queryChild(2)));
            addDependencySource(value, curGraph, activityExpr);
            return true;
        }
    case no_table:
        {
            IHqlExpression * filename = expr->queryChild(0);
            OwnedHqlExpr value = createAttribute(fileAtom, getNormalizedFilename(filename));
            addDependencyUse(value, curGraph, activityExpr);
            return !filename->isConstant();
        }
    case no_select:
        return expr->hasProperty(newAtom);
    case no_workunit_dataset:
        {
            IHqlExpression * sequence = queryPropertyChild(expr, sequenceAtom, 0);
            IHqlExpression * name = queryPropertyChild(expr, nameAtom, 0);
            OwnedHqlExpr value = createAttribute(resultAtom, LINK(sequence), LINK(name));
            addDependencyUse(value, curGraph, activityExpr);
            return false;
        }
    case no_getresult:
        {
            IHqlExpression * sequence = queryPropertyChild(expr, sequenceAtom, 0);
            IHqlExpression * name = queryPropertyChild(expr, namedAtom, 0);
            OwnedHqlExpr value = createAttribute(resultAtom, LINK(sequence), LINK(name));
            addDependencyUse(value, curGraph, activityExpr);
            return false;
        }
    case no_getgraphresult:
        {
            OwnedHqlExpr value = createAttribute(resultAtom, LINK(expr->queryChild(1)), LINK(expr->queryChild(2)));
            addDependencyUse(value, curGraph, activityExpr);
            return false;
        }
    case no_setgraphresult:
        {
            OwnedHqlExpr value = createAttribute(resultAtom, LINK(expr->queryChild(1)), LINK(expr->queryChild(2)));
            addDependencySource(value, curGraph, activityExpr);
            return true;
        }
    case no_ensureresult:
    case no_setresult:
    case no_extractresult:
        {
            IHqlExpression * sequence = queryPropertyChild(expr, sequenceAtom, 0);
            IHqlExpression * name = queryPropertyChild(expr, namedAtom, 0);
            OwnedHqlExpr value = createAttribute(resultAtom, LINK(sequence), LINK(name));
            addDependencySource(value, curGraph, activityExpr);
            return true;
        }
    case no_attr:
    case no_attr_link:
    case no_record:
    case no_field:
        return false; //no need to look any further
    default:
        return true;
    }
}


void EclResourcer::doAddChildDependencies(IHqlExpression * expr, ResourceGraphInfo * graph, IHqlExpression * activityExpr)
{
    if (expr->queryTransformExtra())
        return;
    expr->setTransformExtraUnlinked(expr);

    if (addExprDependency(expr, graph, activityExpr))
    {
        ForEachChild(idx, expr)
            doAddChildDependencies(expr->queryChild(idx), graph, activityExpr);
    }
}

void EclResourcer::addChildDependencies(IHqlExpression * expr, ResourceGraphInfo * graph, IHqlExpression * activityExpr)
{
    if (graph)
    {
        lockTransformMutex();
        doAddChildDependencies(expr, graph, activityExpr);
        unlockTransformMutex();
    }
}

void EclResourcer::addDependencies(IHqlExpression * expr, ResourceGraphInfo * graph, IHqlExpression * activityExpr)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (info && info->containsActivity)
    {
        if (info->isActivity)
        {
            if (info->gatheredDependencies)
                return;
            info->gatheredDependencies = true;
            graph = info->graph;
            activityExpr = expr;
        }
        if (addExprDependency(expr, graph, activityExpr))
        {
            unsigned first = getFirstActivityArgument(expr);
            unsigned last = first + getNumActivityArguments(expr);
            ForEachChild(idx, expr)
            {
                if ((idx >= first) && (idx < last))
                    addDependencies(expr->queryChild(idx), graph, activityExpr);
                else
                    addChildDependencies(expr->queryChild(idx), graph, activityExpr);
            }
        }
    }
    else
        addChildDependencies(expr, graph, activityExpr);

    ForEachItemIn(i, info->childDependents)
    {
        IHqlExpression & cur = info->childDependents.item(i);
        if (isResourcedActivity(&cur))
        {
            addDependencies(&cur, NULL, NULL);
            ResourcerInfo * sourceInfo = queryResourceInfo(&cur);
            sourceInfo->noteUsedFromChild();
            ResourceGraphLink * link = new ResourceGraphDependencyLink(sourceInfo->graph, &cur, graph, expr);
            graph->dependsOn.append(*link);
            links.append(*link);
        }
    }
}

void EclResourcer::addDependencies(HqlExprArray & exprs)
{
    ForEachItemIn(idx, exprs)
        addDependencies(&exprs.item(idx), NULL, NULL);
}

void EclResourcer::spotUnbalancedSplitters(IHqlExpression * expr, unsigned whichSource, IHqlExpression * path, ResourceGraphInfo * graph)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info)
        return;

    if (graph && info->graph && info->graph != graph)
    {
        if ((info->currentSource == whichSource) && (info->pathToSplitter != path))
            graph->unbalancedExternalSources.append(*LINK(expr->queryBody()));
        info->currentSource = whichSource;
        info->pathToSplitter.set(path);
        return;
    }
    else
    {
        if (info->currentSource == whichSource)
        {
            if (info->pathToSplitter != path)
                info->balanced = false;
            return;
        }

        info->currentSource = whichSource;
        info->pathToSplitter.set(path);
    }

    if (info->containsActivity)
    {
        unsigned first = getFirstActivityArgument(expr);
        unsigned num = getNumActivityArguments(expr);
        bool modify = false;
        if (num > 1)
        {
            switch (expr->getOperator())
            {
            case no_addfiles:
                if (expr->hasProperty(_ordered_Atom) || expr->hasProperty(_orderedPull_Atom) || isGrouped(expr))
                    modify = true;
                break;
            default:
                modify = true;
                break;
            }
        }

        unsigned last = first + num;
        for (unsigned idx = first; idx < last; idx++)
        {
            OwnedHqlExpr childPath = modify ? createAttribute(pathAtom, getSizetConstant(idx), LINK(path)) : LINK(path);
            spotUnbalancedSplitters(expr->queryChild(idx), whichSource, childPath, graph);
        }
    }


    //Now check dependencies between graphs (for roxie)
    if (!graph)
    {
        if (info->graph)
        {
            GraphLinkArray & graphLinks = info->graph->dependsOn;
            ForEachItemIn(i, graphLinks)
            {
                ResourceGraphLink & link = graphLinks.item(i);
                if (link.sinkNode == expr)
                {
                    OwnedHqlExpr childPath = createAttribute(dependencyAtom, LINK(link.sourceNode), LINK(path));
                    spotUnbalancedSplitters(link.sourceNode, whichSource, childPath, graph);
                }
            }
        }
        else
        {
            ForEachItemIn(i, links)
            {
                ResourceGraphLink & link = links.item(i);
                if (link.sinkNode == expr)
                {
                    OwnedHqlExpr childPath = createAttribute(dependencyAtom, LINK(link.sourceNode), LINK(path));
                    spotUnbalancedSplitters(link.sourceNode, whichSource, childPath, graph);
                }
            }
        }
    }
}

void EclResourcer::spotUnbalancedSplitters(HqlExprArray & exprs)
{
    unsigned curSource = 1;
    switch (targetClusterType)
    {
    case HThorCluster:
        break;
    case ThorCluster:
    case ThorLCRCluster:
        {
            //Thor only handles one graph at a time, so only walk expressions within a single graph.
            ForEachItemIn(i1, graphs)
            {
                ResourceGraphInfo & curGraph = graphs.item(i1);
                ForEachItemIn(i2, curGraph.sinks)
                {
                    ResourceGraphLink & cur = curGraph.sinks.item(i2);
                    spotUnbalancedSplitters(cur.sourceNode, curSource++, 0, &curGraph);
                }
            }
        }
        break;
    case RoxieCluster:
        {
            //Roxie pulls all at once, so need to analyse globally.
            ForEachItemIn(idx, exprs)
                spotUnbalancedSplitters(&exprs.item(idx), curSource++, 0, NULL);
            break;
        }
    }
}

void EclResourcer::spotSharedInputs(IHqlExpression * expr, ResourceGraphInfo * graph)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info)
        return;

    if (info->graph && info->graph != graph)
    {
        IHqlExpression * body = expr->queryBody();
        if (!graph->unbalancedExternalSources.contains(*body))
            graph->balancedExternalSources.append(*LINK(body));

        return;
    }

    if (info->isSplit())
    {
        //overload currentSource to track if we have visited this splitter before.  It cannot have value value NotFound up to now
        if (info->currentSource == NotFound)
            return;
        info->currentSource = NotFound;
    }

    if (info->containsActivity)
    {
        unsigned first = getFirstActivityArgument(expr);
        unsigned num = getNumActivityArguments(expr);
        unsigned last = first + num;
        for (unsigned idx = first; idx < last; idx++)
        {
            spotSharedInputs(expr->queryChild(idx), graph);
        }
    }
}

void EclResourcer::spotSharedInputs()
{
    //Thor only handles one graph at a time, so only walk expressions within a single graph.
    ForEachItemIn(i1, graphs)
    {
        ResourceGraphInfo & curGraph = graphs.item(i1);
        HqlExprCopyArray visited;
        ForEachItemIn(i2, curGraph.sinks)
        {
            ResourceGraphLink & cur = curGraph.sinks.item(i2);
            IHqlExpression * curExpr = cur.sourceNode;
            if (!visited.contains(*curExpr))
            {
                ResourcerInfo * info = queryResourceInfo(curExpr);
                if (!info->isExternalSpill() && !info->expandRatherThanSpill(true))
                {
                    spotSharedInputs(curExpr, &curGraph);
                    visited.append(*curExpr);
                }
            }
        }
    }
}

//------------------------------------------------------------------------------------------
// PASS6: Merge sub graphs that can share resources and don't have dependencies
// MORE: Once sources are merged, should try merging between trees.

static bool conditionsMatch(const HqlExprArray & left, const HqlExprArray & right)
{
    if (left.ordinality() != right.ordinality())
        return false;

    ForEachItemIn(i, left)
    {
        if (!left.contains(right.item(i)) || !right.contains(left.item(i)))
            return false;
    }
    return true;
}


bool EclResourcer::queryMergeGraphLink(ResourceGraphLink & link)
{
    if (link.linkKind == UnconditionalLink)
    {
        //Don't combine any dependencies 
        const GraphLinkArray & sinks = link.sourceGraph->sinks;
        ForEachItemIn(i1, sinks)
        {
            ResourceGraphLink & cur = sinks.item(i1);
            if (cur.sinkGraph && cur.sourceNode->isAction())
                return false;
        }

        //Roxie pulls all subgraphs at same time, so no problem with conditional links since handled at run time.
        if (options.noConditionalLinks)
            return true;

        //No conditionals in the sink graph=>will be executed just as frequently
        if (!link.sinkGraph->mergedConditionSource)
            return true;

        //Is this the only place this source graph is used?  If so, always fine to merge
        if (sinks.ordinality() == 1)
            return true;

        //1) if context the source graph is being merged into is unconditional, then it is ok [ could have conditional and unconditional paths to same graph]
        //2) if context is conditional, then we don't really want to do it unless the conditions on all sinks are identical, and the only links occur between these two graphs.
        //   (situation occurs with spill fed into two branches of a join).
        bool isConditionalInSinkGraph = false;
        bool accessedFromManyGraphs = false;
        ForEachItemIn(i, sinks)
        {
            ResourceGraphLink & cur = sinks.item(i);
            if (cur.sinkNode)
            {
                if (cur.sinkGraph != link.sinkGraph)
                    accessedFromManyGraphs = true;
                else
                {
                    if (!isConditionalInSinkGraph)
                    {
                        ResourcerInfo * sinkInfo = queryResourceInfo(cur.sinkNode);

                        //If this is conditional, don't merge if there is a link to another graph
                        if ((!cur.isDependency() && sinkInfo->isConditionExpr()) || 
                        //if (sinkInfo->isConditionExpr() || 
                            (!sinkInfo->isUnconditional() && sinkInfo->conditions.ordinality()))
                            isConditionalInSinkGraph = true;
                    }
                }
            }
        }

        if (isConditionalInSinkGraph && accessedFromManyGraphs)
            return false;

        return true;
    }

    return false;
}


unsigned EclResourcer::getMaxDepth() const
{
    unsigned maxDepth = 0;
    for (unsigned idx = 0; idx < graphs.ordinality(); idx++)
    {
        unsigned depth = graphs.item(idx).getDepth();
        if (depth > maxDepth)
            maxDepth = depth;
    }
    return maxDepth;
}


void EclResourcer::mergeSubGraphs(unsigned pass)
{
    unsigned maxDepth = getMaxDepth();
    for (unsigned curDepth = maxDepth+1; curDepth-- != 0;)
    {
mergeAgain:
        for (unsigned idx = 0; idx < graphs.ordinality(); idx++)
        {
            ResourceGraphInfo & cur = graphs.item(idx);
            if ((cur.getDepth() == curDepth) && !cur.isDead)
            {
                bool tryAgain;
                do
                {
                    tryAgain = false;
                    for (unsigned idxSource = 0; idxSource < cur.sources.ordinality(); /*incremented in loop*/)
                    {
                        ResourceGraphLink & curLink = cur.sources.item(idxSource);
                        ResourceGraphInfo * source = curLink.sourceGraph;
                        IHqlExpression * sourceNode = curLink.sourceNode;
                        bool tryToMerge;
                        bool expandSourceInPlace = queryResourceInfo(sourceNode)->expandRatherThanSpill(false);
                        if (pass == 0)
                            tryToMerge = !expandSourceInPlace;
                        else
                            tryToMerge = expandSourceInPlace;

                        if (tryToMerge)
                        {
                            bool ok = true;
                            ResourcerInfo * sourceResourceInfo = queryResourceInfo(sourceNode);
                            if (sourceResourceInfo->outputToUseForSpill && (targetClusterType == HThorCluster))
                            {
                                if (curLink.sinkNode != sourceResourceInfo->outputToUseForSpill)
                                    ok = false;
                            }
                            unsigned curSourceDepth = source->getDepth();
                            //MORE: Merging identical conditionals?
                            if (ok && queryMergeGraphLink(curLink) &&
                                !sourceResourceInfo->expandRatherThanSplit() &&
                                cur.mergeInSource(*source, *resourceLimit, (curLink.linkKind == ConditionalLink)))
                            {
                                //NB: Following cannot remove sources below the current index.
                                replaceGraphReferences(source, &cur);
                                source->isDead = true;
#ifdef VERIFY_RESOURCING
                                checkRecursion(&cur);
#endif
                                unsigned newDepth = cur.getDepth();
                                //Unusual: The source we are merging with has just increased in depth, so any
                                //dependents have also increased in depth.  Need to try again at different depth
                                //to see if one of those will merge in.
                                if (newDepth > curSourceDepth)
                                {
                                    curDepth += (newDepth - curSourceDepth);
                                    goto mergeAgain;
                                }
                                //depth of this element has changed, so don't check to see if it merges with any other
                                //sources on this iteration.
                                if (newDepth != curDepth)
                                {
                                    tryAgain = false;
                                    break;
                                }
                                tryAgain = true;
                            }
                            else
                                idxSource++;
                        }
                        else
                            idxSource++;
                    }
                } while (tryAgain);
            }
        }
    }
}

void EclResourcer::mergeSiblings()
{
    unsigned maxDepth = getMaxDepth();
    for (unsigned curDepth = maxDepth+1; curDepth-- != 0;)
    {
        for (unsigned idx = 0; idx < graphs.ordinality(); idx++)
        {
            ResourceGraphInfo & cur = graphs.item(idx);
            if ((cur.getDepth() == curDepth) && !cur.isDead)
            {
                ForEachItemIn(idxSource, cur.sources)
                {
                    ResourceGraphLink & curLink = cur.sources.item(idxSource);
                    ResourceGraphInfo * source = curLink.sourceGraph;
                    IHqlExpression * sourceNode = curLink.sourceNode;
                    ResourcerInfo * sourceInfo = queryResourceInfo(sourceNode);
                    if (sourceInfo->neverSplit || sourceInfo->expandRatherThanSplit())
                        continue;

                    for (unsigned iSink = 0; iSink < source->sinks.ordinality(); )
                    {
                        ResourceGraphLink & secondLink = source->sinks.item(iSink);
                        ResourceGraphInfo * sink = secondLink.sinkGraph;
                        if (sink && (sink != &cur) && !sink->isDead && sourceNode->queryBody() == secondLink.sourceNode->queryBody())
                        {
                            if (cur.mergeInSibling(*sink, *resourceLimit))
                            {
                                //NB: Following cannot remove sources below the current index.
                                replaceGraphReferences(sink, &cur);
                                sink->isDead = true;
                            }
                            else
                                iSink++;
                        }
                        else
                           iSink++;
                    }
                }
            }
        }
    }
}

void EclResourcer::mergeSubGraphs()
{
    for (unsigned pass=0; pass < 2; pass++)
        mergeSubGraphs(pass);

    if (options.combineSiblings)
        mergeSiblings();

    ForEachItemInRev(idx2, graphs)
    {
        if (graphs.item(idx2).isDead)
            graphs.remove(idx2);
    }
}

//------------------------------------------------------------------------------------------
// PASS7: Optimize aggregates off of splitters into through aggregates.

bool EclResourcer::optimizeAggregate(IHqlExpression * expr)
{
    if (!isSimpleAggregateResult(expr))
        return false;

    //expr is a no_extractresult 
    if (queryResourceInfo(expr)->childDependents.ordinality())
        return false;

    IHqlExpression * row2ds = expr->queryChild(0);          // no_datasetfromrow
    IHqlExpression * selectNth = row2ds->queryChild(0);

    ResourcerInfo * row2dsInfo = queryResourceInfo(row2ds);

    //If more than one set result for the same aggregate don't merge the aggregation because
    //it messes up the internal count.  Should really fix it and do multiple stores in the
    //through aggregate.
    if (row2dsInfo->numInternalUses() > 1)
        return false;

    //Be careful not to lose any spills...
    if (row2dsInfo->numExternalUses)
        return false;

    ResourcerInfo * selectNthInfo = queryResourceInfo(selectNth);
    if (selectNthInfo->numExternalUses)
        return false;

    IHqlExpression * aggregate = selectNth->queryChild(0);      // no_newaggregate
    IHqlExpression * parent = aggregate->queryChild(0);
    ResourcerInfo * info = queryResourceInfo(parent);
    if (info->numInternalUses() <= 1)
        return false;

    //ok, we can go ahead and merge.
    info->aggregates.append(*LINK(expr));
//  info->numExternalUses--;
//  info->numUses--;
    return true;
}


void EclResourcer::optimizeAggregates()
{
    for (unsigned idx = 0; idx < graphs.ordinality(); idx++)
    {
        ResourceGraphInfo & cur = graphs.item(idx);
        for (unsigned idxSink = 0; idxSink < cur.sinks.ordinality(); /*incremented in loop*/)
        {
            ResourceGraphLink & link = cur.sinks.item(idxSink);
            if ((link.sinkGraph == NULL) && optimizeAggregate(link.sourceNode))
                cur.sinks.remove(idxSink);
            else
                idxSink++;
        }
    }
}

//------------------------------------------------------------------------------------------
// PASS8: Improve efficiency by merging the split points slightly

IHqlExpression * EclResourcer::findPredecessor(IHqlExpression * expr, IHqlExpression * search, IHqlExpression * prev)
{
    if (expr == search)
        return prev;

    ResourcerInfo * info = queryResourceInfo(expr);
    if (info && info->containsActivity)
    {
        unsigned first = getFirstActivityArgument(expr);
        unsigned last = first + getNumActivityArguments(expr);
        for (unsigned idx=first; idx < last; idx++)
        {
            IHqlExpression * match = findPredecessor(expr->queryChild(idx), search, expr);
            if (match)
                return match;
        }
    }
    return NULL;
}

IHqlExpression * EclResourcer::findPredecessor(ResourcerInfo * search)
{
    ForEachItemIn(idx, links)
    {
        ResourceGraphLink & cur = links.item(idx);

        if (cur.sourceGraph == search->graph)
        {
            IHqlExpression * match = findPredecessor(cur.sourceNode, search->original, NULL);
            if (match)
                return match;
        }
    }
    return NULL;
}

void EclResourcer::moveExternalSpillPoints()
{
    if (options.minimizeSpillSize == 0)
        return;

    //if we have a external spill point where all the external outputs reduce their data significantly
    //either via a project or a filter, then it might be worth including those activities in the main
    //graph and ,if all external children reduce data, then may be best to filter 
    ForEachItemIn(idx, links)
    {
        ResourceGraphLink & cur = links.item(idx);
        if ((cur.linkKind == UnconditionalLink) && cur.sinkGraph)
        {
            while (lightweightAndReducesDatasetSize(cur.sinkNode))
            {
                ResourcerInfo * sourceInfo = queryResourceInfo(cur.sourceNode);
                if (!sourceInfo->isExternalSpill() || (sourceInfo->numExternalUses > options.minimizeSpillSize))
                    break;

                ResourcerInfo * sinkInfo = queryResourceInfo(cur.sinkNode);
                if (sinkInfo->numInternalUses() != 1)
                    break;

                IHqlExpression * sinkPred = findPredecessor(sinkInfo);
                sinkInfo->graph.set(cur.sourceGraph);
                sourceInfo->numExternalUses--;
                sinkInfo->numExternalUses++;
                cur.sourceNode.set(cur.sinkNode);
                cur.sinkNode.set(sinkPred);
            }
        }
    }
}


//------------------------------------------------------------------------------------------
// PASS9: Create a new expression tree representing the information

static HqlTransformerInfo childDependentReplacerInfo("ChildDependentReplacer");
class ChildDependentReplacer : public MergingHqlTransformer
{
public:
    ChildDependentReplacer(const HqlExprCopyArray & _childDependents, const HqlExprArray & _replacements) 
        : MergingHqlTransformer(childDependentReplacerInfo), childDependents(_childDependents), replacements(_replacements)
    {
    }

protected:
    virtual IHqlExpression * createTransformed(IHqlExpression * expr)
    {
        unsigned match = childDependents.find(*expr);
        if (match != NotFound)
            return LINK(&replacements.item(match));

        return MergingHqlTransformer::createTransformed(expr);
    }

protected:
    const HqlExprCopyArray & childDependents;
    const HqlExprArray & replacements;
};


static IHqlExpression * getScalarReplacement(IHqlExpression * original, IHqlExpression * replacement)
{
    IHqlExpression * value = original;
    //First skip any wrappers which are there to cause things to be hoisted.
    loop
    {
        node_operator op = value->getOperator();
        if ((op != no_globalscope) && (op != no_thisnode) && (op != no_evalonce))
            break;
        value = value->queryChild(0);
    }

    //Now modify the spilled result depending on how the spilled result was created (see EclHoistLocator::noteScalar() above)
    if (value->getOperator() == no_select)
    {
        IHqlExpression * field = value->queryChild(1);
        bool isNew;
        IHqlExpression * ds = querySelectorDataset(value, isNew);
        if(isNew || ds->isDatarow())
        {
            if (projectSelectorDatasetToField(ds))
                return createNewSelectExpr(LINK(replacement), LINK(field));
            return replaceSelectorDataset(value, replacement);
        }
    }
    else if (value->getOperator() == no_createset)
    {
        IHqlExpression * record = replacement->queryRecord();
        IHqlExpression * field = record->queryChild(0);
        return createValue(no_createset, original->getType(), LINK(replacement), createSelectExpr(LINK(replacement->queryNormalizedSelector()), LINK(field)));
    }

    IHqlExpression * record = replacement->queryRecord();
    return createNewSelectExpr(LINK(replacement), LINK(record->queryChild(0)));
}


IHqlExpression * EclResourcer::replaceResourcedReferences(ResourcerInfo * info, IHqlExpression * expr)
{
    if (!isAffectedByResourcing(expr))
        return LINK(expr);

    LinkedHqlExpr mapped = expr;
    if (info && (info->childDependents.ordinality()))
    {
        HqlExprArray replacements;
        ForEachItemIn(i, info->originalChildDependents)
        {
            IHqlExpression & cur = info->childDependents.item(i);
            LinkedHqlExpr replacement = &cur;
            if (isResourcedActivity(&cur))
                replacement.setown(createResourced(&cur, NULL, false, false));

            IHqlExpression * original = &info->originalChildDependents.item(i);
            if (!original->isDataset() && !original->isDatarow())
                replacement.setown(getScalarReplacement(original, replacement));

            replacements.append(*replacement.getClear());
        }

        ChildDependentReplacer replacer(info->originalChildDependents, replacements);
        mapped.setown(replacer.transformRoot(mapped));
    }
    return mapped.getClear();
}

IHqlExpression * EclResourcer::doCreateResourced(IHqlExpression * expr, ResourceGraphInfo * ownerGraph, bool expandInParent, bool defineSideEffect)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    node_operator op = expr->getOperator();
    HqlExprArray args;
    bool same = true;

    unsigned first = getFirstActivityArgument(expr);
    unsigned last = first + getNumActivityArguments(expr);
    OwnedHqlExpr transformed;
    switch (op)
    {
    case no_if:
        {
            ForEachChild(idx, expr)
            {
                IHqlExpression * child = expr->queryChild(idx);
                IHqlExpression * resourced;
                if ((idx < first) || (idx >= last))
                    resourced = replaceResourcedReferences(info, child);
                else
                    resourced = createResourced(child, ownerGraph, expandInParent, false);
                if (child != resourced) 
                    same = false;
                args.append(*resourced);
            }
            break;
        }
    case no_case:
    case no_map:
        UNIMPLEMENTED;
    case no_keyed:
        return LINK(expr);
    case no_compound:
        transformed.setown(createResourced(expr->queryChild(1), ownerGraph, expandInParent, false));
        break;
    case no_executewhen:
        {
            args.append(*createResourced(expr->queryChild(0), ownerGraph, expandInParent, false));
            args.append(*createResourced(expr->queryChild(1), ownerGraph, expandInParent, false));
            assertex(args.item(1).getOperator() == no_callsideeffect);
            unwindChildren(args, expr, 2);
            same = false;
            break;
        }
    case no_join:
    case no_denormalize:
    case no_denormalizegroup:
        if (false)//if (isKeyedJoin(expr))
        {
            args.append(*createResourced(expr->queryChild(0), ownerGraph, expandInParent, false));
            args.append(*LINK(expr->queryChild(1)));
            unsigned max = expr->numChildren();
            for (unsigned idx=2; idx < max; idx++)
                args.append(*replaceResourcedReferences(info, expr->queryChild(idx)));
            same = false;
            break;
        }
        //fall through...
    default:
        {
            IHqlExpression * activeTable = NULL;
            // Check to see if the activity has a dataset which is in scope for the rest of its arguments.
            // If so we'll need to remap references from the children.
            if (hasActiveTopDataset(expr) && (first != last))
                activeTable = expr->queryChild(0);

            ForEachChild(idx, expr)
            {
                IHqlExpression * child = expr->queryChild(idx);
                IHqlExpression * resourced;
                if ((idx < first) || (idx >= last))
                {
                    LinkedHqlExpr mapped = child;
                    if (activeTable && isAffectedByResourcing(child))
                    {
                        IHqlExpression * activeTableTransformed = &args.item(0);
                        if (activeTable != activeTableTransformed)
                            mapped.setown(scopedReplaceSelector(child, activeTable, activeTableTransformed));
                    }
                    resourced = replaceResourcedReferences(info, mapped);
                }
                else
                    resourced = createResourced(child, ownerGraph, expandInParent, false);
                if (child != resourced) 
                    same = false;
                args.append(*resourced);
            }
        }
        break;
    }

    if (!transformed)
        transformed.setown(same ? LINK(expr) : expr->clone(args));

    if (!expandInParent)
    {
        if (!transformed->isAction())
            transformed.setown(info->createTransformedExpr(transformed));
        else if (defineSideEffect)
            transformed.setown(createValue(no_definesideeffect, LINK(transformed), createUniqueId()));
    }

    return transformed.getClear();
}

/*
 Need to be careful because result should not reuse the same expression tree unless that element is a splitter.

createResourced()
{
    if (!isActivity)
        if (!containsActivity)
            replace any refs to the activeTable with whatever it has been mapped to
        else
            recurse
    else if (!isDefinedInSameGraph)
        expand/create reader
        set active table
    else isSplitter and alreadyGeneratedForThisGraph
        return previous result
    else
        create transformed  
}
  */

void EclResourcer::doCheckRecursion(ResourceGraphInfo * graph, PointerArray & visited)
{
    visited.append(graph);
    ForEachItemIn(idxD, graph->dependsOn)
        checkRecursion(graph->dependsOn.item(idxD).sourceGraph, visited);
    ForEachItemIn(idxS, graph->sources)
        checkRecursion(graph->sources.item(idxS).sourceGraph, visited);
    visited.pop();
}

void EclResourcer::checkRecursion(ResourceGraphInfo * graph, PointerArray & visited)
{
    if (visited.find(graph) != NotFound)
        throwUnexpected();
    doCheckRecursion(graph, visited);
}

void EclResourcer::checkRecursion(ResourceGraphInfo * graph)
{
    PointerArray visited;
    doCheckRecursion(graph, visited);
}

IHqlExpression * EclResourcer::createResourced(IHqlExpression * expr, ResourceGraphInfo * ownerGraph, bool expandInParent, bool defineSideEffect)
{
    ResourcerInfo * info = queryResourceInfo(expr);
    if (!info || !info->containsActivity)
        return replaceResourcedReferences(info, expr);

    if (!info->isActivity)
    {
        assertex(!defineSideEffect);
        HqlExprArray args;
        bool same = true;
        ForEachChild(idx, expr)
        {
            IHqlExpression * cur = expr->queryChild(idx);
            IHqlExpression * curResourced = createResourced(cur, ownerGraph, expandInParent, false);
            args.append(*curResourced);
            if (cur != curResourced)
                same = false;
        }
        if (same)
            return LINK(expr);
        return expr->clone(args);
    }

    if (info->graph != ownerGraph)
    {
        assertex(!defineSideEffect);
        bool isShared = options.optimizeSharedInputs && ownerGraph && ownerGraph->isSharedInput(expr);
        if (isShared)
        {
            IHqlExpression * mapped = ownerGraph->queryMappedSharedInput(expr->queryBody());
            if (mapped)
                return LINK(mapped);
        }

        IHqlExpression * source;
        if (info->expandRatherThanSpill(true))
        {
            bool expandChildInParent = options.minimiseSpills ? expandInParent : true;
            OwnedHqlExpr resourced = doCreateResourced(expr, ownerGraph, expandChildInParent, false);
            if (queryAddUniqueToActivity(resourced))
                source = appendUniqueAttr(resourced);
            else
                source = LINK(resourced);
        }
        else
        {
            if (!expr->isAction())
            {
                OwnedHqlExpr reason;
                if (ownerGraph && options.checkResources())
                {
                    StringBuffer reasonText;
                    ownerGraph->getMergeFailReason(reasonText, info->graph, *resourceLimit);
                    if (reasonText.length())
                    {
                        reasonText.insert(0, "Resource limit spill: ");
                        reason.setown(createAttribute(_spillReason_Atom, createConstant(reasonText.str())));
                    }
                }

                source = info->createSpilledRead(reason);
            }
            else
            {
                IHqlExpression * uid = info->transformed->queryProperty(_uid_Atom);
                source = createValue(no_callsideeffect, makeVoidType(), LINK(uid));
                //source = LINK(info->transformed);
            }
        }

        if (isShared)
        {
            source = createDatasetF(no_split, source, createAttribute(balancedAtom), createUniqueId(), NULL);
            ownerGraph->addSharedInput(expr->queryBody(), source);
        }

        return source;
    }

    if (!expandInParent && info->transformed && info->isSplit())
    {
        return LINK(info->transformed);
    }

    OwnedHqlExpr resourced = doCreateResourced(expr, ownerGraph, expandInParent, defineSideEffect);
    if (queryAddUniqueToActivity(resourced))// && !resourced->hasProperty(_internal_Atom))
        resourced.setown(appendUniqueAttr(resourced));

    if (!expandInParent)
    {
        info->transformed = resourced;
    }
    return resourced.getClear();
}

void EclResourcer::createResourced(ResourceGraphInfo * graph, HqlExprArray & transformed)
{
    if (graph->createdGraph || graph->isDead)
        return;
    if (!graph->containsActiveSinks() && (!graph->hasConditionSource))
        return;

#ifdef VERIFY_RESOURCING
    checkRecursion(graph);
#endif
//  DBGLOG("Prepare to CreateResourced(%p)", graph);
    if (graph->startedGeneratingResourced)
        throwError(HQLWRN_RecursiveDependendencies);

    graph->startedGeneratingResourced = true;
    ForEachItemIn(idxD, graph->dependsOn)
        createResourced(graph->dependsOn.item(idxD).sourceGraph, transformed);
    ForEachItemIn(idxS, graph->sources)
        createResourced(graph->sources.item(idxS).sourceGraph, transformed);

//  DBGLOG("Create resourced %p", graph);

    //First generate the graphs for all the unconditional sinks
    HqlExprArray args;
    ForEachItemIn(idx, graph->sinks)
    {
        ResourceGraphLink & sink = graph->sinks.item(idx);
        IHqlExpression * sinkNode = sink.sourceNode;
        ResourcerInfo * info = queryResourceInfo(sinkNode);
        //If graph is unconditional, any condition sinks are forced to be generated (and spilt)
        if (!info->transformed)
        {
            // if it is a spiller, then it will be generated from another sink
            if (!info->isExternalSpill())
            {
                IHqlExpression * resourced = createResourced(sinkNode, graph, false, sinkNode->isAction() && sink.sinkGraph);
                assertex(info->transformed);
                args.append(*resourced);
            }
        }
    }

    ForEachItemIn(i2, graph->sinks)
    {
        ResourceGraphLink & sink = graph->sinks.item(i2);
        IHqlExpression * sinkNode = sink.sourceNode;
        ResourcerInfo * info = queryResourceInfo(sinkNode);
        IHqlExpression * splitter = info->splitterOutput;
        if (splitter && !args.contains(*splitter))
            args.append(*LINK(splitter));
    }

    if (args.ordinality() == 0)
        graph->isDead = true;
    else
    {
        if (options.useGraphResults)
            args.append(*createAttribute(childAtom));
        graph->createdGraph.setown(createValue(no_subgraph, makeVoidType(), args));
        transformed.append(*LINK(graph->createdGraph));
    }
}


void EclResourcer::inheritRedundantDependencies(ResourceGraphInfo * thisGraph)
{
    if (thisGraph->inheritedExpandedDependencies)
        return;
    thisGraph->inheritedExpandedDependencies = true;
    ForEachItemIn(idx, thisGraph->sources)
    {
        ResourceGraphLink & cur = thisGraph->sources.item(idx);
        if (cur.isRedundantLink())
        {
            inheritRedundantDependencies(cur.sourceGraph);
            ForEachItemIn(i, cur.sourceGraph->dependsOn)
            {
                ResourceGraphLink & curDepend = cur.sourceGraph->dependsOn.item(i);
                ResourceGraphLink * link = new ResourceGraphDependencyLink(curDepend.sourceGraph, curDepend.sourceNode, thisGraph, cur.sinkNode);
                thisGraph->dependsOn.append(*link);
                links.append(*link);
            }
        }
    }
}


void EclResourcer::createResourced(HqlExprArray & transformed)
{
    //Before removing null links (e.g., where the source graph is expanded inline), need to make sure
    //dependencies are cloned, otherwise graphs can be generated in the wrong order
    ForEachItemIn(idx1, graphs)
        inheritRedundantDependencies(&graphs.item(idx1));

    ForEachItemInRev(idx2, links)
    {
        ResourceGraphLink & cur = links.item(idx2);
        if (cur.isRedundantLink())
            removeLink(cur, true);
    }

    ForEachItemIn(idx3, graphs)
        createResourced(&graphs.item(idx3), transformed);
}

static int compareGraphDepth(CInterface * * _l, CInterface * * _r)
{
    ResourceGraphInfo * l = (ResourceGraphInfo *)*_l;
    ResourceGraphInfo * r = (ResourceGraphInfo *)*_r;
    return l->getDepth() - r->getDepth();
}

static int compareLinkDepth(CInterface * * _l, CInterface * * _r)
{
    ResourceGraphLink * l = (ResourceGraphLink *)*_l;
    ResourceGraphLink * r = (ResourceGraphLink *)*_r;
    int diff = l->sourceGraph->getDepth() - r->sourceGraph->getDepth();
    if (diff) return diff;
    if (l->sinkGraph)
        if (r->sinkGraph)
            return l->sinkGraph->getDepth() - r->sinkGraph->getDepth();
        else
            return -1;
    else
        if (r->sinkGraph)
            return +1;
        else
            return 0;
}

void EclResourcer::display(StringBuffer & out)
{
    CIArrayOf<ResourceGraphInfo> sortedGraphs;
    ForEachItemIn(j1, graphs)
        sortedGraphs.append(OLINK(graphs.item(j1)));
    sortedGraphs.sort(compareGraphDepth);

    out.append("Graphs:\n");
    ForEachItemIn(i, sortedGraphs)
    {
        ResourceGraphInfo & cur = sortedGraphs.item(i);
        out.appendf("%d: depth(%d) uncond(%d) cond(%d) %s {%p}\n", i, cur.getDepth(), cur.isUnconditional, cur.hasConditionSource, cur.isDead ? "dead" : "", &cur);
        ForEachItemIn(j, cur.sources)
        {
            ResourceGraphLink & link = cur.sources.item(j);
            out.appendf("  Source: %p %s\n", link.sinkNode.get(), getOpString(link.sinkNode->getOperator()));
        }
        ForEachItemIn(k, cur.sinks)
        {
            ResourceGraphLink & link = cur.sinks.item(k);
            IHqlExpression * sourceNode = link.sourceNode;
            ResourcerInfo * sourceInfo = queryResourceInfo(sourceNode);
            out.appendf("  Sink: %p %s cond(%d,%d) int(%d) ext(%d)\n", sourceNode, getOpString(sourceNode->getOperator()), sourceInfo->conditions.ordinality(), sourceInfo->conditionSourceCount, sourceInfo->numInternalUses(), sourceInfo->numExternalUses);
        }
        ForEachItemIn(i3, dependencySource.graphs)
        {
            if (&dependencySource.graphs.item(i3) == &cur)
            {
                StringBuffer s;
                toECL(&dependencySource.search.item(i3), s);
                out.appendf("  Creates: %s\n", s.str());
            }
        }
    }
    out.append("Links:\n");

    CIArrayOf<ResourceGraphLink> sortedLinks;
    ForEachItemIn(j2, links)
        sortedLinks.append(OLINK(links.item(j2)));
    sortedLinks.sort(compareLinkDepth);
    ForEachItemIn(i2, sortedLinks)
    {
        ResourceGraphLink & link = sortedLinks.item(i2);
        unsigned len = out.length();
        out.appendf("  Source: %d %s", sortedGraphs.find(*link.sourceGraph), getOpString(link.sourceNode->getOperator()));
        if (link.sinkNode)
        {
            out.padTo(len+30);
            out.appendf("  Sink: %d %s", sortedGraphs.find(*link.sinkGraph), getOpString(link.sinkNode->getOperator()));
        }
        if (link.linkKind == ConditionalLink)
            out.append(" <conditional>");
        else if (link.linkKind == SequenceLink)
            out.append(" <sequence>");
        out.newline();
    }
}

void EclResourcer::trace()
{
    StringBuffer s;
    display(s);
    DBGLOG("%s", s.str());
}

//---------------------------------------------------------------------------

void EclResourcer::resourceGraph(HqlExprArray & exprs, HqlExprArray & transformed)
{
    //NB: This only resources a single level of queries.  SubQueries should be resourced in a separate
    //pass so that commonality between different activities/subgraphs isn't introduced/messed up.
    findSplitPoints(exprs);
    createInitialGraphs(exprs);
    markConditions(exprs);
    if (options.checkResources())
        resourceSubGraphs(exprs);
    addDependencies(exprs);
#ifdef TRACE_RESOURCING
    trace();
#endif
    mergeSubGraphs();
#ifdef TRACE_RESOURCING
    trace();
#endif
    spotUnbalancedSplitters(exprs);
    if (options.optimizeSharedInputs)
        spotSharedInputs();

    if (spotThroughAggregate)
        optimizeAggregates();
    moveExternalSpillPoints();
    createResourced(transformed);
}


void EclResourcer::resourceRemoteGraph(HqlExprArray & exprs, HqlExprArray & transformed)
{
    //NB: This only resources a single level of queries.  SubQueries should be resourced in a separate
    //pass so that commonality between different activities/subgraphs isn't introduced/messed up.
    findSplitPoints(exprs);
    createInitialRemoteGraphs(exprs);
    markConditions(exprs);
    addDependencies(exprs);
#ifdef TRACE_RESOURCING
    trace();
#endif
    mergeSubGraphs();
#ifdef TRACE_RESOURCING
    trace();
#endif
    createResourced(transformed);
}


//---------------------------------------------------------------------------

void expandLists(HqlExprArray & args, IHqlExpression * expr)
{
    switch (expr->getOperator())
    {
    case no_comma:
    case no_compound:
    case no_parallel:       
    case no_actionlist:
        // for the moment, expand root parallel nodes, it generates much better code.
        // I should really come up with a better way of implementing sequential/parallel.
        {
            ForEachChild(idx, expr)
                expandLists(args, expr->queryChild(idx));
            break;
        }
    default:
        args.append(*LINK(expr));
        break;
    }
}

IHqlExpression * resourceThorGraph(HqlCppTranslator & translator, IHqlExpression * expr, ClusterType targetClusterType, unsigned clusterSize, IHqlExpression * graphIdExpr)
{
    HqlExprArray transformed;
    {
        EclResourcer resourcer(translator.queryErrors(), translator.wu(), targetClusterType, clusterSize, translator.queryOptions());
        if (graphIdExpr)
            resourcer.setNewChildQuery(graphIdExpr, 0);

        HqlExprArray exprs;
        expandLists(exprs, expr);
        resourcer.resourceGraph(exprs, transformed);
    }
    hoistNestedCompound(translator, transformed);
    return createActionList(transformed);
}


static IHqlExpression * doResourceGraph(HqlCppTranslator & translator, HqlExprCopyArray * activeRows, IHqlExpression * expr, 
                                        ClusterType targetClusterType, unsigned clusterSize,
                                        IHqlExpression * graphIdExpr, unsigned * numResults, bool isChild, bool useGraphResults)
{
    HqlExprArray transformed;
    {
        EclResourcer resourcer(translator.queryErrors(), translator.wu(), targetClusterType, clusterSize, translator.queryOptions());
        if (isChild)
            resourcer.setChildQuery(true);
        resourcer.setNewChildQuery(graphIdExpr, *numResults);
        resourcer.setUseGraphResults(useGraphResults);

        if (activeRows)
            resourcer.tagActiveCursors(*activeRows);

        HqlExprArray exprs;
        expandLists(exprs, expr);

        resourcer.resourceGraph(exprs, transformed);
        *numResults = resourcer.numGraphResults();
    }
    hoistNestedCompound(translator, transformed);
    return createActionList(transformed);
}


IHqlExpression * resourceLibraryGraph(HqlCppTranslator & translator, IHqlExpression * expr, ClusterType targetClusterType, unsigned clusterSize, IHqlExpression * graphIdExpr, unsigned * numResults)
{
    return doResourceGraph(translator, NULL, expr, targetClusterType, clusterSize, graphIdExpr, numResults, false, true);       //?? what value for isChild (e.g., thor library call).  Need to gen twice?
}


IHqlExpression * resourceNewChildGraph(HqlCppTranslator & translator, HqlExprCopyArray & activeRows, IHqlExpression * expr, ClusterType targetClusterType, IHqlExpression * graphIdExpr, unsigned * numResults)
{
    return doResourceGraph(translator, &activeRows, expr, targetClusterType, 0, graphIdExpr, numResults, true, true);
}

IHqlExpression * resourceLoopGraph(HqlCppTranslator & translator, HqlExprCopyArray & activeRows, IHqlExpression * expr, ClusterType targetClusterType, IHqlExpression * graphIdExpr, unsigned * numResults, bool insideChildQuery)
{
    return doResourceGraph(translator, &activeRows, expr, targetClusterType, 0, graphIdExpr, numResults, insideChildQuery, true);
}

IHqlExpression * resourceRemoteGraph(HqlCppTranslator & translator, IHqlExpression * expr, ClusterType targetClusterType, unsigned clusterSize)
{
    HqlExprArray transformed;
    {
        EclResourcer resourcer(translator.queryErrors(), translator.wu(), targetClusterType, clusterSize, translator.queryOptions());

        HqlExprArray exprs;
        expandLists(exprs, expr);

        resourcer.resourceRemoteGraph(exprs, transformed);
    }
    hoistNestedCompound(translator, transformed);
    return createActionList(transformed);
}


/*
Conditions:

They are nasty.  We process the tree in two passes.  First we tag anything which must be evaluated, and
save a list of condition statements to process later.
Second pass we tag conditionals.
a) all left and right branches of a condition are tagged. [conditionSourceCount]
b) all conditional expressions are tagged with the conditions they are evaluated for.
   [if the condition lists match then it should be possible to merge the graphs]
c) The spill count for an node should ignore the number of links from conditional graphs,
   but should add the number of conditions.
d) if (a, b(f1) +b(f2), c) needs to link b twice though!

*/

/*
This transformer converts spill activities to no_dataset/no_output, and also converts splitters of splitters into
a single splitter.
*/

class SpillActivityTransformer : public NewHqlTransformer
{
public:
    SpillActivityTransformer();

protected:
    virtual void analyseExpr(IHqlExpression * expr);
    virtual IHqlExpression * createTransformed(IHqlExpression * expr);

    bool isUnbalanced(IHqlExpression * body)
    {
        ANewTransformInfo * info = queryTransformExtra(body);
        return info->spareByte1 != 0;
    }
    void setUnbalanced(IHqlExpression * body)
    {
        ANewTransformInfo * info = queryTransformExtra(body);
        info->spareByte1 = true;
    }
};

static HqlTransformerInfo spillActivityTransformerInfo("SpillActivityTransformer");
SpillActivityTransformer::SpillActivityTransformer() 
: NewHqlTransformer(spillActivityTransformerInfo)
{ 
}

void SpillActivityTransformer::analyseExpr(IHqlExpression * expr)
{
    IHqlExpression * body = expr->queryBody();
    if (alreadyVisited(body))
        return;
    if (body->getOperator() == no_split)
    {
        IHqlExpression * input = body->queryChild(0);
        if (input->getOperator() == no_split)
        {
            loop
            {
                IHqlExpression * cur = input->queryChild(0);
                if (cur->getOperator() != no_split)
                    break;
                input = cur;
            }
            if (!body->hasProperty(balancedAtom))
                setUnbalanced(input->queryBody());
        }
    }
    NewHqlTransformer::analyseExpr(expr);
}

IHqlExpression * SpillActivityTransformer::createTransformed(IHqlExpression * expr)
{
    IHqlExpression * annotation = queryTransformAnnotation(expr);
    if (annotation)
        return annotation;

    switch (expr->getOperator())
    {
    case no_split:
        {
            IHqlExpression * input = expr->queryChild(0);
            if (input->getOperator() == no_split)
                return transform(input);
            OwnedHqlExpr transformed = NewHqlTransformer::createTransformed(expr);
            if (transformed->hasProperty(balancedAtom) && isUnbalanced(expr))
                return removeProperty(transformed, balancedAtom);
            return transformed.getClear();
        }
    case no_writespill:
        {
            HqlExprArray args;
            transformChildren(expr, args);
            return createValue(no_output, makeVoidType(), args);
        }
    case no_commonspill:
        return transform(expr->queryChild(0));
    case no_readspill:
        {
            OwnedHqlExpr ds = transform(expr->queryChild(0));
            HqlExprArray args;
            args.append(*transform(expr->queryChild(1)));
            args.append(*LINK(ds->queryRecord()));
            ForEachChildFrom(i, expr, 2)
            {
                IHqlExpression * cur = expr->queryChild(i);
                args.append(*transform(cur));
            }
            IHqlExpression * recordCountAttr = queryRecordCountInfo(expr);
            if (recordCountAttr)
                args.append(*LINK(recordCountAttr));
            return createDataset(no_table, args);
        }
    }
    return NewHqlTransformer::createTransformed(expr);
}

IHqlExpression * convertSpillsToActivities(IHqlExpression * expr)
{
    SpillActivityTransformer transformer;
    transformer.analyse(expr, 0);
    return transformer.transformRoot(expr);
}