Merge 2a49c31 into 1607944

prune_shard_list.c

@@ -39,10 +39,20 @@
 #include "utils/errcodes.h"
 #include "utils/lsyscache.h"
 #include "utils/typcache.h"
+#include "utils/memutils.h"
+
+
+/*
+ * OperatorTypeCache is used for caching base operator types for given typeId,
+ * accessMethodId and strategyNumber. It is initialized to empty list as
+ * there are no items in the cache.
+ */
+static List *OperatorTypeCache = NIL;
 
 
 /* local function forward declarations */
 static Oid GetOperatorByType(Oid typeId, Oid accessMethodId, int16 strategyNumber);
+static Oid LookupOperatorByType(Oid typeId, Oid accessMethodId, int16 strategyNumber);
 static bool SimpleOpExpression(Expr *clause);
 static Node * HashableClauseMutator(Node *originalNode, Var *partitionColumn);
 static bool OpExpressionContainsColumn(OpExpr *operatorExpression, Var *partitionColumn);
@@ -218,7 +228,7 @@ MakeOpExpression(Var *variable, int16 strategyNumber)
 	OpExpr *expression = NULL;
 
 	/* Load the operator from system catalogs */
-	operatorId = GetOperatorByType(typeId, accessMethodId, strategyNumber);
+	operatorId = LookupOperatorByType(typeId, accessMethodId, strategyNumber);
 
 	constantValue = makeNullConst(typeId, typeModId, collationId);
 
@@ -238,6 +248,51 @@ MakeOpExpression(Var *variable, int16 strategyNumber)
 }
 
 
+/*
+ * LookupOperatorByType is a wrapper around GetOperatorByType that uses a cache
+ * to avoid multiple lookups of operators by their types.
+ */
+static Oid
+LookupOperatorByType(Oid typeId, Oid accessMethodId, int16 strategyNumber)
+{
+	OperatorTypeCacheEntry *matchingCacheEntry = NULL;
+	ListCell *cacheEntryCell = NULL;
+
+	/* search the cache */
+	foreach(cacheEntryCell, OperatorTypeCache)
+	{
+		OperatorTypeCacheEntry *cacheEntry = lfirst(cacheEntryCell);
+
+		if (cacheEntry->typeId == typeId && cacheEntry->accessMethodId == accessMethodId
+			&& cacheEntry->strategyNumber == strategyNumber)
+		{
+			matchingCacheEntry = cacheEntry;
+			break;
+		}
+	}
+
+	/* if not found in the cache, call GetOperatorByType and put the result in cache */
+	if (matchingCacheEntry == NULL)
+	{
+		Oid operatorId = GetOperatorByType(typeId, accessMethodId, strategyNumber);
+		MemoryContext oldContext = MemoryContextSwitchTo(CacheMemoryContext);
+
+		matchingCacheEntry = palloc0(sizeof(OperatorTypeCacheEntry));
+		matchingCacheEntry->typeId = typeId;
+		matchingCacheEntry->accessMethodId = accessMethodId;
+		matchingCacheEntry->strategyNumber = strategyNumber;
+
+		matchingCacheEntry->operatorId = operatorId;
+
+		OperatorTypeCache = lappend(OperatorTypeCache, matchingCacheEntry);
+
+		MemoryContextSwitchTo(oldContext);
+	}
+
+	return matchingCacheEntry->operatorId;
+}
+
+
 /*
  * GetOperatorByType returns the operator oid for the given type, access
  * method, and strategy number.

prune_shard_list.h

@@ -31,6 +31,21 @@
 #define RESERVED_HASHED_COLUMN_ID MaxAttrNumber
 
 
+/*
+ * OperatorTypeCacheEntry contains the information for a cache entry in
+ * operator type cache.
+ */
+typedef struct OperatorTypeCacheEntry
+{
+	/* cache key consists of typeId, accessMethodId and strategyNumber */
+	Oid typeId;
+	Oid accessMethodId;
+	int16 strategyNumber;
+
+	Oid operatorId;
+} OperatorTypeCacheEntry;
+
+
 /* function declarations for shard pruning */
 extern List * PruneShardList(Oid relationId, List *whereClauseList,
 							 List *shardIntervalList);