From 4816d2ea3250b0f1e43d8b5521b9bf951821a945 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 11 Oct 2012 12:20:56 -0400 Subject: [PATCH] Fix cross-type case in partial row matching for hashed subplans. When hashing a subplan like "WHERE (a, b) NOT IN (SELECT x, y FROM ...)", findPartialMatch() attempted to match rows using the hashtable's internal equality operators, which of course are for x and y's datatypes. What we need to use are the potentially cross-type operators for a=x, b=y, etc. Failure to do that leads to wrong answers or even crashes. The scope for problems is limited to cases where we have different types with compatible hash functions (else we'd not be using a hashed subplan), but for example int4 vs int8 can cause the problem. Per bug #7597 from Bo Jensen. This has been wrong since the hashed-subplan code was written, so patch all the way back. --- src/backend/executor/nodeSubplan.c | 17 +++++++++++------ src/test/regress/expected/subselect.out | 17 +++++++++++++++++ src/test/regress/sql/subselect.sql | 15 +++++++++++++++ 3 files changed, 43 insertions(+), 6 deletions(-) diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c index d615b78373..b501fc4f03 100644 --- a/src/backend/executor/nodeSubplan.c +++ b/src/backend/executor/nodeSubplan.c @@ -46,7 +46,8 @@ static Datum ExecScanSubPlan(SubPlanState *node, ExprContext *econtext, bool *isNull); static void buildSubPlanHash(SubPlanState *node, ExprContext *econtext); -static bool findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot); +static bool findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot, + FmgrInfo *eqfunctions); static bool slotAllNulls(TupleTableSlot *slot); static bool slotNoNulls(TupleTableSlot *slot); @@ -153,7 +154,7 @@ ExecHashSubPlan(SubPlanState *node, return BoolGetDatum(true); } if (node->havenullrows && - findPartialMatch(node->hashnulls, slot)) + findPartialMatch(node->hashnulls, slot, node->cur_eq_funcs)) { ExecClearTuple(slot); *isNull = true; @@ -186,14 +187,14 @@ ExecHashSubPlan(SubPlanState *node, } /* Scan partly-null table first, since more likely to get a match */ if (node->havenullrows && - findPartialMatch(node->hashnulls, slot)) + findPartialMatch(node->hashnulls, slot, node->cur_eq_funcs)) { ExecClearTuple(slot); *isNull = true; return BoolGetDatum(false); } if (node->havehashrows && - findPartialMatch(node->hashtable, slot)) + findPartialMatch(node->hashtable, slot, node->cur_eq_funcs)) { ExecClearTuple(slot); *isNull = true; @@ -573,9 +574,13 @@ buildSubPlanHash(SubPlanState *node, ExprContext *econtext) * We have to scan the whole hashtable; we can't usefully use hashkeys * to guide probing, since we might get partial matches on tuples with * hashkeys quite unrelated to what we'd get from the given tuple. + * + * Caller must provide the equality functions to use, since in cross-type + * cases these are different from the hashtable's internal functions. */ static bool -findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot) +findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot, + FmgrInfo *eqfunctions) { int numCols = hashtable->numCols; AttrNumber *keyColIdx = hashtable->keyColIdx; @@ -588,7 +593,7 @@ findPartialMatch(TupleHashTable hashtable, TupleTableSlot *slot) ExecStoreMinimalTuple(entry->firstTuple, hashtable->tableslot, false); if (!execTuplesUnequal(slot, hashtable->tableslot, numCols, keyColIdx, - hashtable->cur_eq_funcs, + eqfunctions, hashtable->tempcxt)) { TermTupleHashIterator(&hashiter); diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out index 30cff04cb7..6a81df9538 100644 --- a/src/test/regress/expected/subselect.out +++ b/src/test/regress/expected/subselect.out @@ -543,6 +543,23 @@ from ----- (0 rows) +-- +-- Test case for cross-type partial matching in hashed subplan (bug #7597) +-- +create temp table outer_7597 (f1 int4, f2 int4); +insert into outer_7597 values (0, 0); +insert into outer_7597 values (1, 0); +insert into outer_7597 values (0, null); +insert into outer_7597 values (1, null); +create temp table inner_7597(c1 int8, c2 int8); +insert into inner_7597 values(0, null); +select * from outer_7597 where (f1, f2) not in (select * from inner_7597); + f1 | f2 +----+---- + 1 | 0 + 1 | +(2 rows) + -- -- Test case for premature memory release during hashing of subplan output -- diff --git a/src/test/regress/sql/subselect.sql b/src/test/regress/sql/subselect.sql index e07a30ed03..cba449a203 100644 --- a/src/test/regress/sql/subselect.sql +++ b/src/test/regress/sql/subselect.sql @@ -345,6 +345,21 @@ from join int4_tbl i4 on dummy = i4.f1; +-- +-- Test case for cross-type partial matching in hashed subplan (bug #7597) +-- + +create temp table outer_7597 (f1 int4, f2 int4); +insert into outer_7597 values (0, 0); +insert into outer_7597 values (1, 0); +insert into outer_7597 values (0, null); +insert into outer_7597 values (1, null); + +create temp table inner_7597(c1 int8, c2 int8); +insert into inner_7597 values(0, null); + +select * from outer_7597 where (f1, f2) not in (select * from inner_7597); + -- -- Test case for premature memory release during hashing of subplan output -- -- 2.40.0