Add support for cross-type hashing in hash index searches and hash joins.

Hashing for aggregation purposes still needs work, so it's not time to
mark any cross-type operators as hashable for general use, but these cases
work if the operators are so marked by hand in the system catalogs.

src/backend/access/hash/hashsearch.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.47 2007/01/20 18:43:35 neilc Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.48 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -115,6 +115,7 @@ _hash_first(IndexScanDesc scan, ScanDirection dir)
 {
 	Relation	rel = scan->indexRelation;
 	HashScanOpaque so = (HashScanOpaque) scan->opaque;
+	ScanKey		cur;
 	uint32		hashkey;
 	Bucket		bucket;
 	BlockNumber blkno;
@@ -143,18 +144,37 @@ _hash_first(IndexScanDesc scan, ScanDirection dir)
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 				 errmsg("hash indexes do not support whole-index scans")));
 
+	/* There may be more than one index qual, but we hash only the first */
+	cur = &scan->keyData[0];
+
+	/* We support only single-column hash indexes */
+	Assert(cur->sk_attno == 1);
+	/* And there's only one operator strategy, too */
+	Assert(cur->sk_strategy == HTEqualStrategyNumber);
+
 	/*
 	 * If the constant in the index qual is NULL, assume it cannot match any
 	 * items in the index.
 	 */
-	if (scan->keyData[0].sk_flags & SK_ISNULL)
+	if (cur->sk_flags & SK_ISNULL)
 		return false;
 
 	/*
 	 * Okay to compute the hash key.  We want to do this before acquiring any
 	 * locks, in case a user-defined hash function happens to be slow.
+	 *
+	 * If scankey operator is not a cross-type comparison, we can use the
+	 * cached hash function; otherwise gotta look it up in the catalogs.
+	 *
+	 * We support the convention that sk_subtype == InvalidOid means the
+	 * opclass input type; this is a hack to simplify life for ScanKeyInit().
 	 */
-	hashkey = _hash_datum2hashkey(rel, scan->keyData[0].sk_argument);
+	if (cur->sk_subtype == rel->rd_opcintype[0] ||
+		cur->sk_subtype == InvalidOid)
+		hashkey = _hash_datum2hashkey(rel, cur->sk_argument);
+	else
+		hashkey = _hash_datum2hashkey_type(rel, cur->sk_argument,
+										   cur->sk_subtype);
 
 	/*
 	 * Acquire shared split lock so we can compute the target bucket safely

src/backend/access/hash/hashutil.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.50 2007/01/05 22:19:22 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.51 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,6 +18,7 @@
 #include "access/hash.h"
 #include "access/reloptions.h"
 #include "executor/execdebug.h"
+#include "utils/lsyscache.h"
 
 
 /*
@@ -63,6 +64,9 @@ _hash_checkqual(IndexScanDesc scan, IndexTuple itup)
 
 /*
  * _hash_datum2hashkey -- given a Datum, call the index's hash procedure
+ *
+ * The Datum is assumed to be of the index's column type, so we can use the
+ * "primary" hash procedure that's tracked for us by the generic index code.
  */
 uint32
 _hash_datum2hashkey(Relation rel, Datum key)
@@ -75,6 +79,31 @@ _hash_datum2hashkey(Relation rel, Datum key)
 	return DatumGetUInt32(FunctionCall1(procinfo, key));
 }
 
+/*
+ * _hash_datum2hashkey_type -- given a Datum of a specified type,
+ *			hash it in a fashion compatible with this index
+ *
+ * This is much more expensive than _hash_datum2hashkey, so use it only in
+ * cross-type situations.
+ */
+uint32
+_hash_datum2hashkey_type(Relation rel, Datum key, Oid keytype)
+{
+	RegProcedure hash_proc;
+
+	/* XXX assumes index has only one attribute */
+	hash_proc = get_opfamily_proc(rel->rd_opfamily[0],
+								  keytype,
+								  keytype,
+								  HASHPROC);
+	if (!RegProcedureIsValid(hash_proc))
+		elog(ERROR, "missing support function %d(%u,%u) for index \"%s\"",
+			 HASHPROC, keytype, keytype,
+			 RelationGetRelationName(rel));
+
+	return DatumGetUInt32(OidFunctionCall1(hash_proc, key));
+}
+
 /*
  * _hash_hashkey2bucket -- determine which bucket the hashkey maps to.
  */

src/backend/executor/execGrouping.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/execGrouping.c,v 1.23 2007/01/10 18:06:02 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/execGrouping.c,v 1.24 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -224,15 +224,18 @@ execTuplesHashPrepare(int numCols,
 	{
 		Oid			eq_opr = eqOperators[i];
 		Oid			eq_function;
-		Oid			hash_function;
+		Oid			left_hash_function;
+		Oid			right_hash_function;
 
 		eq_function = get_opcode(eq_opr);
-		hash_function = get_op_hash_function(eq_opr);
-		if (!OidIsValid(hash_function)) /* should not happen */
+		if (!get_op_hash_functions(eq_opr,
+								   &left_hash_function, &right_hash_function))
 			elog(ERROR, "could not find hash function for hash operator %u",
 				 eq_opr);
+		/* For the moment, we're not supporting cross-type cases here */
+		Assert(left_hash_function == right_hash_function);
 		fmgr_info(eq_function, &(*eqFunctions)[i]);
-		fmgr_info(hash_function, &(*hashFunctions)[i]);
+		fmgr_info(right_hash_function, &(*hashFunctions)[i]);
 	}
 }
 

src/backend/executor/nodeHash.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.109 2007/01/28 23:21:26 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeHash.c,v 1.110 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -94,7 +94,7 @@ MultiExecHash(HashState *node)
 			break;
 		/* We have to compute the hash value */
 		econtext->ecxt_innertuple = slot;
-		if (ExecHashGetHashValue(hashtable, econtext, hashkeys, false,
+		if (ExecHashGetHashValue(hashtable, econtext, hashkeys, false, false,
 								 &hashvalue))
 		{
 			ExecHashTableInsert(hashtable, slot, hashvalue);
@@ -267,19 +267,23 @@ ExecHashTableCreate(Hash *node, List *hashOperators)
 	 * Also remember whether the join operators are strict.
 	 */
 	nkeys = list_length(hashOperators);
-	hashtable->hashfunctions = (FmgrInfo *) palloc(nkeys * sizeof(FmgrInfo));
+	hashtable->outer_hashfunctions =
+		(FmgrInfo *) palloc(nkeys * sizeof(FmgrInfo));
+	hashtable->inner_hashfunctions =
+		(FmgrInfo *) palloc(nkeys * sizeof(FmgrInfo));
 	hashtable->hashStrict = (bool *) palloc(nkeys * sizeof(bool));
 	i = 0;
 	foreach(ho, hashOperators)
 	{
 		Oid			hashop = lfirst_oid(ho);
-		Oid			hashfn;
+		Oid			left_hashfn;
+		Oid			right_hashfn;
 
-		hashfn = get_op_hash_function(hashop);
-		if (!OidIsValid(hashfn))
+		if (!get_op_hash_functions(hashop, &left_hashfn, &right_hashfn))
 			elog(ERROR, "could not find hash function for hash operator %u",
 				 hashop);
-		fmgr_info(hashfn, &hashtable->hashfunctions[i]);
+		fmgr_info(left_hashfn, &hashtable->outer_hashfunctions[i]);
+		fmgr_info(right_hashfn, &hashtable->inner_hashfunctions[i]);
 		hashtable->hashStrict[i] = op_strict(hashop);
 		i++;
 	}
@@ -674,10 +678,12 @@ bool
 ExecHashGetHashValue(HashJoinTable hashtable,
 					 ExprContext *econtext,
 					 List *hashkeys,
+					 bool outer_tuple,
 					 bool keep_nulls,
 					 uint32 *hashvalue)
 {
 	uint32		hashkey = 0;
+	FmgrInfo   *hashfunctions;
 	ListCell   *hk;
 	int			i = 0;
 	MemoryContext oldContext;
@@ -690,6 +696,11 @@ ExecHashGetHashValue(HashJoinTable hashtable,
 
 	oldContext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
 
+	if (outer_tuple)
+		hashfunctions = hashtable->outer_hashfunctions;
+	else
+		hashfunctions = hashtable->inner_hashfunctions;
+
 	foreach(hk, hashkeys)
 	{
 		ExprState  *keyexpr = (ExprState *) lfirst(hk);
@@ -728,8 +739,7 @@ ExecHashGetHashValue(HashJoinTable hashtable,
 			/* Compute the hash function */
 			uint32		hkey;
 
-			hkey = DatumGetUInt32(FunctionCall1(&hashtable->hashfunctions[i],
-												keyval));
+			hkey = DatumGetUInt32(FunctionCall1(&hashfunctions[i], keyval));
 			hashkey ^= hkey;
 		}
 

src/backend/executor/nodeHashjoin.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeHashjoin.c,v 1.87 2007/01/28 23:21:26 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeHashjoin.c,v 1.88 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -569,6 +569,7 @@ ExecHashJoinOuterGetTuple(PlanState *outerNode,
 			econtext->ecxt_outertuple = slot;
 			if (ExecHashGetHashValue(hashtable, econtext,
 									 hjstate->hj_OuterHashKeys,
+									 true, /* outer tuple */
 									 (hjstate->js.jointype == JOIN_LEFT),
 									 hashvalue))
 			{

src/backend/executor/nodeSubplan.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.82 2007/01/05 22:19:28 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeSubplan.c,v 1.83 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -792,7 +792,8 @@ ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
 			Expr	   *expr;
 			TargetEntry *tle;
 			GenericExprState *tlestate;
-			Oid			hashfn;
+			Oid			left_hashfn;
+			Oid			right_hashfn;
 
 			Assert(IsA(fstate, FuncExprState));
 			Assert(IsA(opexpr, OpExpr));
@@ -830,12 +831,14 @@ ExecInitSubPlan(SubPlanState *node, EState *estate, int eflags)
 			fmgr_info(opexpr->opfuncid, &node->eqfunctions[i - 1]);
 			node->eqfunctions[i - 1].fn_expr = (Node *) opexpr;
 
-			/* Lookup the associated hash function */
-			hashfn = get_op_hash_function(opexpr->opno);
-			if (!OidIsValid(hashfn))
+			/* Lookup the associated hash functions */
+			if (!get_op_hash_functions(opexpr->opno,
+									   &left_hashfn, &right_hashfn))
 				elog(ERROR, "could not find hash function for hash operator %u",
 					 opexpr->opno);
-			fmgr_info(hashfn, &node->hashfunctions[i - 1]);
+			/* For the moment, not supporting cross-type cases */
+			Assert(left_hashfn == right_hashfn);
+			fmgr_info(right_hashfn, &node->hashfunctions[i - 1]);
 
 			i++;
 		}

src/backend/optimizer/plan/createplan.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.223 2007/01/22 01:35:20 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.224 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -716,10 +716,10 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path)
 		numGroups = (long) Min(best_path->rows, (double) LONG_MAX);
 
 		/*
-		 * Get the (presumed hashable) equality operators for the Agg node
-		 * to use.  Normally these are the same as the IN clause operators,
-		 * but if those are cross-type operators then the equality operators
-		 * are the ones for the IN clause operators' RHS datatype.
+		 * Get the hashable equality operators for the Agg node to use.
+		 * Normally these are the same as the IN clause operators, but if
+		 * those are cross-type operators then the equality operators are
+		 * the ones for the IN clause operators' RHS datatype.
 		 */
 		groupOperators = (Oid *) palloc(numGroupCols * sizeof(Oid));
 		groupColPos = 0;
@@ -728,8 +728,7 @@ create_unique_plan(PlannerInfo *root, UniquePath *best_path)
 			Oid			in_oper = lfirst_oid(l);
 			Oid			eq_oper;
 
-			eq_oper = get_compatible_hash_operator(in_oper, false);
-			if (!OidIsValid(eq_oper))		/* shouldn't happen */
+			if (!get_compatible_hash_operators(in_oper, NULL, &eq_oper))
 				elog(ERROR, "could not find compatible hash operator for operator %u",
 					 in_oper);
 			groupOperators[groupColPos++] = eq_oper;

src/backend/utils/cache/lsyscache.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.146 2007/01/22 01:35:21 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.147 2007/01/30 01:33:36 tgl Exp $
  *
  * NOTES
  *	  Eventually, the index information should go through here, too.
@@ -389,23 +389,34 @@ get_mergejoin_opfamilies(Oid opno)
 }
 
 /*
- * get_compatible_hash_operator
- *		Get the OID of a hash equality operator compatible with the given
- *		operator, but operating on its LHS or RHS datatype as specified.
+ * get_compatible_hash_operators
+ *		Get the OID(s) of hash equality operator(s) compatible with the given
+ *		operator, but operating on its LHS and/or RHS datatype.
  *
- * If the given operator is not cross-type, the result should be the same
- * operator, but in cross-type situations it is different.
+ * An operator for the LHS type is sought and returned into *lhs_opno if
+ * lhs_opno isn't NULL.  Similarly, an operator for the RHS type is sought
+ * and returned into *rhs_opno if rhs_opno isn't NULL.
  *
- * Returns InvalidOid if no compatible operator can be found.  (This indicates
- * that the operator should not have been marked oprcanhash.)
+ * If the given operator is not cross-type, the results should be the same
+ * operator, but in cross-type situations they will be different.
+ *
+ * Returns true if able to find the requested operator(s), false if not.
+ * (This indicates that the operator should not have been marked oprcanhash.)
  */
-Oid
-get_compatible_hash_operator(Oid opno, bool use_lhs_type)
+bool
+get_compatible_hash_operators(Oid opno,
+							  Oid *lhs_opno, Oid *rhs_opno)
 {
-	Oid			result = InvalidOid;
+	bool		result = false;
 	CatCList   *catlist;
 	int			i;
 
+	/* Ensure output args are initialized on failure */
+	if (lhs_opno)
+		*lhs_opno = InvalidOid;
+	if (rhs_opno)
+		*rhs_opno = InvalidOid;
+
 	/*
 	 * Search pg_amop to see if the target operator is registered as the "="
 	 * operator of any hash opfamily.  If the operator is registered in
@@ -423,22 +434,53 @@ get_compatible_hash_operator(Oid opno, bool use_lhs_type)
 		if (aform->amopmethod == HASH_AM_OID &&
 			aform->amopstrategy == HTEqualStrategyNumber)
 		{
-			/* Found a suitable opfamily, get matching single-type operator */
-			Oid		typid;
-
 			/* No extra lookup needed if given operator is single-type */
 			if (aform->amoplefttype == aform->amoprighttype)
 			{
-				result = opno;
+				if (lhs_opno)
+					*lhs_opno = opno;
+				if (rhs_opno)
+					*rhs_opno = opno;
+				result = true;
 				break;
 			}
-			typid = use_lhs_type ? aform->amoplefttype : aform->amoprighttype;
-			result = get_opfamily_member(aform->amopfamily,
-										 typid, typid,
-										 HTEqualStrategyNumber);
-			if (OidIsValid(result))
+			/*
+			 * Get the matching single-type operator(s).  Failure probably
+			 * shouldn't happen --- it implies a bogus opfamily --- but
+			 * continue looking if so.
+			 */
+			if (lhs_opno)
+			{
+				*lhs_opno = get_opfamily_member(aform->amopfamily,
+												aform->amoplefttype,
+												aform->amoplefttype,
+												HTEqualStrategyNumber);
+				if (!OidIsValid(*lhs_opno))
+					continue;
+				/* Matching LHS found, done if caller doesn't want RHS */
+				if (!rhs_opno)
+				{
+					result = true;
+					break;
+				}
+			}
+			if (rhs_opno)
+			{
+				*rhs_opno = get_opfamily_member(aform->amopfamily,
+												aform->amoprighttype,
+												aform->amoprighttype,
+												HTEqualStrategyNumber);
+				if (!OidIsValid(*rhs_opno))
+				{
+					/* Forget any LHS operator from this opfamily */
+					if (lhs_opno)
+						*lhs_opno = InvalidOid;
+					continue;
+				}
+				/* Matching RHS found, so done */
+				result = true;
 				break;
-			/* failure probably shouldn't happen, but keep looking if so */
+			}
 		}
 	}
 
@@ -448,28 +490,38 @@ get_compatible_hash_operator(Oid opno, bool use_lhs_type)
 }
 
 /*
- * get_op_hash_function
- *		Get the OID of the datatype-specific hash function associated with
- *		a hashable equality operator.
+ * get_op_hash_functions
+ *		Get the OID(s) of hash support function(s) compatible with the given
+ *		operator, operating on its LHS and/or RHS datatype as required.
  *
- * XXX API needs to be generalized for the case of different left and right
- * datatypes.
+ * A function for the LHS type is sought and returned into *lhs_procno if
+ * lhs_procno isn't NULL.  Similarly, a function for the RHS type is sought
+ * and returned into *rhs_procno if rhs_procno isn't NULL.
  *
- * Returns InvalidOid if no hash function can be found.  (This indicates
- * that the operator should not have been marked oprcanhash.)
+ * If the given operator is not cross-type, the results should be the same
+ * function, but in cross-type situations they will be different.
+ *
+ * Returns true if able to find the requested function(s), false if not.
+ * (This indicates that the operator should not have been marked oprcanhash.)
  */
-Oid
-get_op_hash_function(Oid opno)
+bool
+get_op_hash_functions(Oid opno,
+					  RegProcedure *lhs_procno, RegProcedure *rhs_procno)
 {
-	Oid			result = InvalidOid;
+	bool		result = false;
 	CatCList   *catlist;
 	int			i;
 
+	/* Ensure output args are initialized on failure */
+	if (lhs_procno)
+		*lhs_procno = InvalidOid;
+	if (rhs_procno)
+		*rhs_procno = InvalidOid;
+
 	/*
 	 * Search pg_amop to see if the target operator is registered as the "="
 	 * operator of any hash opfamily.  If the operator is registered in
-	 * multiple opfamilies, assume we can use the associated hash function from
-	 * any one.
+	 * multiple opfamilies, assume we can use any one.
 	 */
 	catlist = SearchSysCacheList(AMOPOPID, 1,
 								 ObjectIdGetDatum(opno),
@@ -483,12 +535,50 @@ get_op_hash_function(Oid opno)
 		if (aform->amopmethod == HASH_AM_OID &&
 			aform->amopstrategy == HTEqualStrategyNumber)
 		{
-			/* Found a suitable opfamily, get matching hash support function */
-			result = get_opfamily_proc(aform->amopfamily,
-									   aform->amoplefttype,
-									   aform->amoprighttype,
-									   HASHPROC);
-			break;
+			/*
+			 * Get the matching support function(s).  Failure probably
+			 * shouldn't happen --- it implies a bogus opfamily --- but
+			 * continue looking if so.
+			 */
+			if (lhs_procno)
+			{
+				*lhs_procno = get_opfamily_proc(aform->amopfamily,
+												aform->amoplefttype,
+												aform->amoplefttype,
+												HASHPROC);
+				if (!OidIsValid(*lhs_procno))
+					continue;
+				/* Matching LHS found, done if caller doesn't want RHS */
+				if (!rhs_procno)
+				{
+					result = true;
+					break;
+				}
+				/* Only one lookup needed if given operator is single-type */
+				if (aform->amoplefttype == aform->amoprighttype)
+				{
+					*rhs_procno = *lhs_procno;
+					result = true;
+					break;
+				}
+			}
+			if (rhs_procno)
+			{
+				*rhs_procno = get_opfamily_proc(aform->amopfamily,
+												aform->amoprighttype,
+												aform->amoprighttype,
+												HASHPROC);
+				if (!OidIsValid(*rhs_procno))
+				{
+					/* Forget any LHS function from this opfamily */
+					if (lhs_procno)
+						*lhs_procno = InvalidOid;
+					continue;
+				}
+				/* Matching RHS found, so done */
+				result = true;
+				break;
+			}
 		}
 	}
 

src/include/access/hash.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/hash.h,v 1.75 2007/01/20 18:43:35 neilc Exp $
+ * $PostgreSQL: pgsql/src/include/access/hash.h,v 1.76 2007/01/30 01:33:36 tgl Exp $
  *
  * NOTES
  *		modeled after Margo Seltzer's hash implementation for unix.
@@ -308,6 +308,7 @@ extern bool _hash_step(IndexScanDesc scan, Buffer *bufP, ScanDirection dir);
 /* hashutil.c */
 extern bool _hash_checkqual(IndexScanDesc scan, IndexTuple itup);
 extern uint32 _hash_datum2hashkey(Relation rel, Datum key);
+extern uint32 _hash_datum2hashkey_type(Relation rel, Datum key, Oid keytype);
 extern Bucket _hash_hashkey2bucket(uint32 hashkey, uint32 maxbucket,
 					 uint32 highmask, uint32 lowmask);
 extern uint32 _hash_log2(uint32 num);

src/include/executor/hashjoin.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/hashjoin.h,v 1.43 2007/01/28 23:21:26 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/executor/hashjoin.h,v 1.44 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -102,12 +102,11 @@ typedef struct HashJoinTableData
 
 	/*
 	 * Info about the datatype-specific hash functions for the datatypes being
-	 * hashed.	We assume that the inner and outer sides of each hashclause
-	 * are the same type, or at least share the same hash function. This is an
-	 * array of the same length as the number of hash keys.
+	 * hashed. These are arrays of the same length as the number of hash join
+	 * clauses (hash keys).
 	 */
-	FmgrInfo   *hashfunctions;	/* lookup data for hash functions */
-
+	FmgrInfo   *outer_hashfunctions;	/* lookup data for hash functions */
+	FmgrInfo   *inner_hashfunctions;	/* lookup data for hash functions */
 	bool	   *hashStrict;		/* is each hash join operator strict? */
 
 	Size		spaceUsed;		/* memory space currently used by tuples */

src/include/executor/nodeHash.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/nodeHash.h,v 1.43 2007/01/28 23:21:26 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/executor/nodeHash.h,v 1.44 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -31,6 +31,7 @@ extern void ExecHashTableInsert(HashJoinTable hashtable,
 extern bool ExecHashGetHashValue(HashJoinTable hashtable,
 					 ExprContext *econtext,
 					 List *hashkeys,
+					 bool outer_tuple,
 					 bool keep_nulls,
 					 uint32 *hashvalue);
 extern void ExecHashGetBucketAndBatch(HashJoinTable hashtable,

src/include/utils/lsyscache.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.115 2007/01/22 01:35:22 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.116 2007/01/30 01:33:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,8 +42,10 @@ extern bool get_compare_function_for_ordering_op(Oid opno,
 extern Oid	get_equality_op_for_ordering_op(Oid opno);
 extern Oid	get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
 extern List *get_mergejoin_opfamilies(Oid opno);
-extern Oid	get_compatible_hash_operator(Oid opno, bool use_lhs_type);
-extern Oid	get_op_hash_function(Oid opno);
+extern bool get_compatible_hash_operators(Oid opno,
+										  Oid *lhs_opno, Oid *rhs_opno);
+extern bool get_op_hash_functions(Oid opno,
+					  RegProcedure *lhs_procno, RegProcedure *rhs_procno);
 extern void get_op_btree_interpretation(Oid opno,
 							List **opfamilies, List **opstrats);
 extern bool ops_in_same_btree_opfamily(Oid opno1, Oid opno2);