ORCA: use backtrace replace the foreach nested foreach

Author: jiaqizho

src/backend/gporca/libgpopt/include/gpopt/operators/CPhysical.h

@@ -158,6 +158,9 @@ class CPhysical : public COperator
 	// total number of optimization requests
 	ULONG m_ulTotalOptRequests;
 
+	void BackTraceOptRequests(const ULONG *ulOptReqs, ULONG ulOptReqsSize,
+	UlongPtrArray *pdrgpulpOptReqsExpanded, ULONG_PTR *current, ULONG cursz);
+
 	// update number of requests of a given property
 	void UpdateOptRequests(ULONG ulPropIndex, ULONG ulRequests);
 

src/backend/gporca/libgpopt/src/operators/CPhysical.cpp

@@ -58,6 +58,22 @@ CPhysical::CPhysical(CMemoryPool *mp)
 	m_phmrcr = GPOS_NEW(mp) ReqdColsReqToColRefSetMap(mp);
 }
 
+void
+CPhysical::BackTraceOptRequests(const ULONG *ulOptReqs, ULONG ulOptReqsSize,
+	UlongPtrArray *pdrgpulpOptReqsExpanded, ULONG_PTR *current, ULONG cursz) {
+	if (cursz == ulOptReqsSize) {
+		ULONG_PTR *copyOne = GPOS_NEW_ARRAY(m_mp, ULONG_PTR, GPOPT_PLAN_PROPS);
+		clib::Memcpy(copyOne, current, GPOPT_PLAN_PROPS * sizeof(ULONG));
+		pdrgpulpOptReqsExpanded->Append(copyOne);
+		return;
+	}
+
+	for (ULONG i = 0; i < ulOptReqs[cursz]; i++) {
+		current[cursz++] = i;
+		BackTraceOptRequests(ulOptReqs, ulOptReqsSize, pdrgpulpOptReqsExpanded, current, cursz);
+		cursz--;
+	}
+}
 
 //---------------------------------------------------------------------------
 //	@function:
@@ -88,37 +104,17 @@ CPhysical::UpdateOptRequests(ULONG ulPropIndex, ULONG ulRequests)
 	m_ulTotalOptRequests = ulOptReqs;
 
 	// update expanded requests
-	const ULONG ulOrderRequests = UlOrderRequests();
-	const ULONG ulDistrRequests = UlDistrRequests();
-	const ULONG ulRewindRequests = UlRewindRequests();
-	const ULONG ulPartPropagateRequests = UlPartPropagateRequests();
+	ULONG ulaOptReqs[GPOPT_PLAN_PROPS] = {
+		UlOrderRequests(), UlDistrRequests(),
+		UlRewindRequests(), UlPartPropagateRequests()
+	};
 
 	CRefCount::SafeRelease(m_pdrgpulpOptReqsExpanded);
-	m_pdrgpulpOptReqsExpanded = nullptr;
 	m_pdrgpulpOptReqsExpanded = GPOS_NEW(m_mp) UlongPtrArray(m_mp);
-	for (ULONG ulOrder = 0; ulOrder < ulOrderRequests; ulOrder++)
-	{
-		for (ULONG ulDistr = 0; ulDistr < ulDistrRequests; ulDistr++)
-		{
-			for (ULONG ulRewind = 0; ulRewind < ulRewindRequests; ulRewind++)
-			{
-				for (ULONG ulPartPropagate = 0;
-					 ulPartPropagate < ulPartPropagateRequests;
-					 ulPartPropagate++)
-				{
-					ULONG_PTR *pulpRequest =
-						GPOS_NEW_ARRAY(m_mp, ULONG_PTR, GPOPT_PLAN_PROPS);
 
-					pulpRequest[0] = ulOrder;
-					pulpRequest[1] = ulDistr;
-					pulpRequest[2] = ulRewind;
-					pulpRequest[3] = ulPartPropagate;
-
-					m_pdrgpulpOptReqsExpanded->Append(pulpRequest);
-				}
-			}
-		}
-	}
+	ULONG_PTR *pulpRequest = GPOS_NEW_ARRAY(m_mp, ULONG_PTR, GPOPT_PLAN_PROPS);
+	BackTraceOptRequests(ulaOptReqs, GPOPT_PLAN_PROPS, m_pdrgpulpOptReqsExpanded, pulpRequest, 0);
+	GPOS_DELETE_ARRAY(pulpRequest);
 }