Mark left dataset of join sorted even if global

Previously the function to indicate that the left hand side of a join
was sorted was never set for a global join.  However thor does correctly
support it if the dataset is globally sorted.
Also add flags to indicate if left/right are locally sorted to
potentially avoid some work in the sorting.

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>

ecl/hqlcpp/hqlcpp.ipp

@@ -1722,7 +1722,7 @@ protected:
     void generateSerializeAssigns(BuildCtx & ctx, IHqlExpression * record, IHqlExpression * selector, IHqlExpression * selfSelect, IHqlExpression * leftSelect, const DatasetReference & srcDataset, const DatasetReference & tgtDataset, HqlExprArray & srcSelects, HqlExprArray & tgtSelects, bool needToClear);
     void generateSerializeFunction(BuildCtx & ctx, const char * funcName, bool serialize, const DatasetReference & srcDataset, const DatasetReference & tgtDataset, HqlExprArray & srcSelects, HqlExprArray & tgtSelects);
     void generateSerializeKey(BuildCtx & ctx, node_operator side, const DatasetReference & dataset, HqlExprArray & sorts, bool isGlobal, bool generateCompares, bool canReuseLeft);             //NB: sorts are ats.xyz
-    void generateSortCompare(BuildCtx & nestedctx, BuildCtx & ctx, node_operator index, const DatasetReference & dataset, HqlExprArray & sorts, bool canRemoveSort, IHqlExpression * noSortAttr, bool canReuseLeft, bool isLightweight);
+    void generateSortCompare(BuildCtx & nestedctx, BuildCtx & ctx, node_operator index, const DatasetReference & dataset, HqlExprArray & sorts, bool canRemoveSort, IHqlExpression * noSortAttr, bool canReuseLeft, bool isLightweight, bool isLocal);
     void addSchemaField(IHqlExpression *field, MemoryBuffer &schema, IHqlExpression *selector);
     void addSchemaFields(IHqlExpression * record, MemoryBuffer &schema, IHqlExpression *selector);
     void addSchemaResource(int seq, const char * name, IHqlExpression * record);

ecl/hqlcpp/hqlhtcpp.cpp

@@ -10749,7 +10749,7 @@ void HqlCppTranslator::buildSlidingMatchFunction(BuildCtx & ctx, HqlExprArray &
     doCompareLeftRight(ctx, funcname, datasetL, datasetR, left, right);
 }
 
-void HqlCppTranslator::generateSortCompare(BuildCtx & nestedctx, BuildCtx & ctx, node_operator side, const DatasetReference & dataset, HqlExprArray & sorts, bool canRemoveSort, IHqlExpression * noSortAttr, bool canReuseLeft, bool isLightweight)
+void HqlCppTranslator::generateSortCompare(BuildCtx & nestedctx, BuildCtx & ctx, node_operator side, const DatasetReference & dataset, HqlExprArray & sorts, bool canRemoveSort, IHqlExpression * noSortAttr, bool canReuseLeft, bool isLightweight, bool isLocal)
 {
     StringBuffer s, compareName;
 
@@ -10757,7 +10757,7 @@ void HqlCppTranslator::generateSortCompare(BuildCtx & nestedctx, BuildCtx & ctx,
     compareName.append("compare").append(sideText);
 
     assertex(dataset.querySide() == no_activetable);
-    bool noNeedToSort = canRemoveSort && isAlreadySorted(dataset.queryDataset(), sorts, canRemoveSort, true);
+    bool noNeedToSort = canRemoveSort && isAlreadySorted(dataset.queryDataset(), sorts, isLocal, true);
     if (userPreventsSort(noSortAttr, side))
         noNeedToSort = true;
     
@@ -11277,12 +11277,12 @@ ABoundActivity * HqlCppTranslator::doBuildActivityJoinOrDenormalize(BuildCtx & c
     bool canReuseLeft = recordTypesMatch(dataset1, dataset2) && arraysMatch(leftSorts, rightSorts);
     if (!isAllJoin)
     {
-        bool canRemoveSort = isLocalJoin || !targetThor();
+        bool isLocalSort = isLocalJoin || !targetThor();
         //Lookup join doesn't need the left sort (unless it is reused elsewhere), or the right sort unless it is deduping.
         if (canReuseLeft || !isLookupJoin)
-            generateSortCompare(instance->nestedctx, instance->classctx, no_left, lhsDsRef, leftSorts, canRemoveSort, noSortAttr, false, isLightweight);
+            generateSortCompare(instance->nestedctx, instance->classctx, no_left, lhsDsRef, leftSorts, true, noSortAttr, false, isLightweight, isLocalSort);
         if (!(isLookupJoin && isManyLookup && !couldBeKeepOne && !targetThor()))            // many lookup doesn't need to dedup the rhs
-            generateSortCompare(instance->nestedctx, instance->classctx, no_right, rhsDsRef, rightSorts, canRemoveSort, noSortAttr, canReuseLeft, isLightweight);
+            generateSortCompare(instance->nestedctx, instance->classctx, no_right, rhsDsRef, rightSorts, isLocalSort, noSortAttr, canReuseLeft, isLightweight, isLocalSort);
 
         bool isGlobal = !isLocalJoin && !instance->isChildActivity();
         generateSerializeKey(instance->nestedctx, no_left, lhsDsRef, leftSorts, isGlobal, false, false);
@@ -11315,6 +11315,11 @@ ABoundActivity * HqlCppTranslator::doBuildActivityJoinOrDenormalize(BuildCtx & c
     if (isLimitedSubstringJoin)
         flags.append("|JFlimitedprefixjoin");
 
+    if (isAlreadySorted(dataset1, leftSorts, true, true) || userPreventsSort(noSortAttr, no_left))
+        flags.append("|JFleftSortedLocally");
+    if (isAlreadySorted(dataset2, rightSorts, true, true) || userPreventsSort(noSortAttr, no_right))
+        flags.append("|JFrightSortedLocally");
+
     if (flags.length())
         doBuildUnsignedFunction(instance->classctx, "getJoinFlags", flags.str()+1);
 

rtl/include/eclhelper.hpp

@@ -1554,6 +1554,8 @@ enum {
     JFdynamicindexfilename       = 0x00800000,
     JFlimitedprefixjoin          = 0x01000000,
     JFindexfromactivity          = 0x02000000,
+    JFleftSortedLocally          = 0x04000000,
+    JFrightSortedLocally         = 0x08000000,
 };
 
 // FetchFlags