database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-30 21:42:05 +03:00
Code Activity

Fix potential failure when hashing the output of a subplan that produces

Browse Source 
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.
This commit is contained in:
Tom Lane
2010-07-28 04:50:50 +00:00
parent 4ff9c8dd48
commit 133924e13e
4 changed files with 36 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
src/include/nodes/execnodes.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.219 2010/02/26 02:01:25 momjian Exp $
* $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.220 2010/07/28 04:50:50 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -699,8 +699,9 @@ 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 *tab_hash_funcs; /* hash functions for table datatype(s) */
FmgrInfo *tab_eq_funcs; /* equality functions for table datatype(s) */