Outer Filter should not pushed down in a partition selector in subquery with...

Outer Filter should not pushed down in a partition selector in subquery with limit clause [#133827909]

The bug is in derivation of required partition propagation specification
from the child. Before this fix, we were pushing the partition
constraints below Limit which will return wrong results.

libgpopt/include/gpopt/operators/CPhysical.h

@@ -64,6 +64,14 @@ namespace gpopt
 				EceoSentinel
 			};
 
+			enum EPropogatePartConstraint
+			{
+				EppcAllowed,
+				EppcProhibited,
+
+				EppcSentinel
+			};
+
 		private:
 
 			//---------------------------------------------------------------------------
@@ -321,7 +329,8 @@ namespace gpopt
 				(
 				IMemoryPool *pmp,
 				CExpressionHandle &exprhdl,
-				CPartitionPropagationSpec *pppsRequired
+				CPartitionPropagationSpec *pppsRequired,
+				EPropogatePartConstraint eppcPropogate
 				);
 			
 			// pass cte requirement to the child

libgpopt/src/operators/CPhysical.cpp

@@ -934,7 +934,8 @@ CPhysical::PppsRequiredPushThruUnresolvedUnary
 	(
 	IMemoryPool *pmp,
 	CExpressionHandle &exprhdl,
-	CPartitionPropagationSpec *pppsRequired
+	CPartitionPropagationSpec *pppsRequired,
+	EPropogatePartConstraint eppcPropogate
 	)
 {
 	GPOS_ASSERT(NULL != pppsRequired);
@@ -962,7 +963,13 @@ CPhysical::PppsRequiredPushThruUnresolvedUnary
 		{
 			// push requirements to child node
 			ppimResult->AddRequiredPartPropagation(ppimReqd, ulPartIndexId, CPartIndexMap::EppraPreservePropagators);
-			(void) ppfmResult->FCopyPartFilter(pmp, ulPartIndexId, ppfmReqd);
+			if (CPhysical::EppcAllowed == eppcPropogate)
+			{
+				// for some logical operators such as limit while we push the part index map, we cannot push the constraints
+				// since they are NOT semantically equivalent. So only push the constraints when the operator asks this
+				// utility function to do so
+				(void) ppfmResult->FCopyPartFilter(pmp, ulPartIndexId, ppfmReqd);
+			}
 		}
 	}
 	

libgpopt/src/operators/CPhysicalAgg.cpp

@@ -430,7 +430,7 @@ CPhysicalAgg::PppsRequired
 	GPOS_ASSERT(0 == ulChildIndex);
 	GPOS_ASSERT(NULL != pppsRequired);
 
-	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired);
+	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired, CPhysical::EppcAllowed);
 }
 
 //---------------------------------------------------------------------------

libgpopt/src/operators/CPhysicalLimit.cpp

@@ -282,7 +282,12 @@ CPhysicalLimit::PppsRequired
 	GPOS_ASSERT(0 == ulChildIndex);
 	GPOS_ASSERT(NULL != pppsRequired);
 	
-	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired);
+	// limit should not push predicate below it as it will generate wrong results
+	// for example, the following two queries are not equivalent.
+	// Q1: select * from (select * from foo order by a limit 1) x where x.a = 10
+	// Q2: select * from (select * from foo where a = 10 order by a limit 1) x
+
+	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired, CPhysical::EppcProhibited);
 }
 
 //---------------------------------------------------------------------------

libgpopt/src/operators/CPhysicalSequenceProject.cpp

@@ -413,7 +413,7 @@ CPhysicalSequenceProject::PppsRequired
 	GPOS_ASSERT(0 == ulChildIndex);
 	GPOS_ASSERT(NULL != pppsRequired);
 
-	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired);
+	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired, CPhysical::EppcAllowed);
 }
 
 //---------------------------------------------------------------------------

libgpopt/src/operators/CPhysicalSort.cpp

@@ -228,7 +228,7 @@ CPhysicalSort::PppsRequired
 	GPOS_ASSERT(0 == ulChildIndex);
 	GPOS_ASSERT(NULL != pppsRequired);
 	
-	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired);
+	return CPhysical::PppsRequiredPushThruUnresolvedUnary(pmp, exprhdl, pppsRequired, CPhysical::EppcAllowed);
 }
 
 //---------------------------------------------------------------------------

server/src/unittest/gpopt/minidump/CPartTblTest.cpp

@@ -28,6 +28,7 @@ ULONG CPartTblTest::m_ulPartTblTestCounter = 0;  // start from first test
 // minidump files
 const CHAR *rgszPartTblFileNames[] =
 	{
+	"../data/dxl/minidump/DonotPushPartConstThruLimit.mdp",
 	"../data/dxl/minidump/PartTbl-DPE-Correlated-NLOuter.mdp",
 	"../data/dxl/minidump/Select-Over-PartTbl.mdp",
 	"../data/dxl/minidump/PartTbl-DPE.mdp",