diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2010-07-28 04:51:21 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2010-07-28 04:51:21 +0000 |
| commit | 44b16a2cf51a66c475a53435755724cd5cbbbd4e (patch) | |
| tree | 6820ebf58460872065fe4f3d694e221d57bfe9f9 /src/include | |
| parent | e83657973771cd58bcf3fc9389247478bc51e6e6 (diff) | |
Fix potential failure when hashing the output of a subplan that produces
a pass-by-reference datatype with a nontrivial projection step.
We were using the same memory context for the projection operation as for
the temporary context used by the hashtable routines in execGrouping.c.
However, the hashtable routines feel free to reset their temp context at
any time, which'd lead to destroying input data that was still needed.
Report and diagnosis by Tao Ma.
Back-patch to 8.1, where the problem was introduced by the changes that
allowed us to work with "virtual" tuples instead of materializing intermediate
tuple values everywhere. The earlier code looks quite similar, but it doesn't
suffer the problem because the data gets copied into another context as a
result of having to materialize ExecProject's output tuple.
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/nodes/execnodes.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h index e981a6a933b..84bf53f956e 100644 --- a/src/include/nodes/execnodes.h +++ b/src/include/nodes/execnodes.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.161.2.2 2007/04/26 23:24:57 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.161.2.3 2010/07/28 04:51:20 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -589,8 +589,9 @@ typedef struct SubPlanState TupleHashTable hashnulls; /* hash table for rows with null(s) */ bool havehashrows; /* TRUE if hashtable is not empty */ bool havenullrows; /* TRUE if hashnulls is not empty */ - MemoryContext tablecxt; /* memory context containing tables */ - ExprContext *innerecontext; /* working context for comparisons */ + MemoryContext hashtablecxt; /* memory context containing hash tables */ + MemoryContext hashtempcxt; /* temp memory context for hash tables */ + ExprContext *innerecontext; /* econtext for computing inner tuples */ AttrNumber *keyColIdx; /* control data for hash tables */ FmgrInfo *eqfunctions; /* comparison functions for hash tables */ FmgrInfo *hashfunctions; /* lookup data for hash functions */ |