database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-10-22 14:32:25 +03:00
Code Activity

Fix problems with cached tuple descriptors disappearing while still in use

Browse Source 
by creating a reference-count mechanism, similar to what we did a long time
ago for catcache entries.  The back branches have an ugly solution involving
lots of extra copies, but this way is more efficient.  Reference counting is
only applied to tupdescs that are actually in caches --- there seems no need
to use it for tupdescs that are generated in the executor, since they'll go
away during plan shutdown by virtue of being in the per-query memory context.
Neil Conway and Tom Lane
This commit is contained in:
Tom Lane
2006-06-16 18:42:24 +00:00
parent b49ce32da1
commit 06e10abc0b
36 changed files with 581 additions and 246 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/include/access/tupdesc.h
View File

@@ -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/access/tupdesc.h,v 1.49 2006/03/16 00:31:55 tgl Exp $
* $PostgreSQL: pgsql/src/include/access/tupdesc.h,v 1.50 2006/06/16 18:42:23 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -57,6 +57,14 @@ typedef struct tupleConstr
* tdtypeid is RECORDOID, and tdtypmod can be either -1 for a fully anonymous
* row type, or a value >= 0 to allow the rowtype to be looked up in the
* typcache.c type cache.
*
* Tuple descriptors that live in caches (relcache or typcache, at present)
* are reference-counted: they can be deleted when their reference count goes
* to zero. Tuple descriptors created by the executor need no reference
* counting, however: they are simply created in the appropriate memory
* context and go away when the context is freed. We set the tdrefcount
* field of such a descriptor to -1, while reference-counted descriptors
* always have tdrefcount >= 0.
*/
typedef struct tupleDesc
{
@@ -67,6 +75,7 @@ typedef struct tupleDesc
Oid tdtypeid; /* composite type ID for tuple type */
int32 tdtypmod; /* typmod for tuple type */
bool tdhasoid; /* tuple has oid attribute in its header */
int tdrefcount; /* reference count, or -1 if not counting */
} *TupleDesc;
@@ -81,6 +90,21 @@ extern TupleDesc CreateTupleDescCopyConstr(TupleDesc tupdesc);
extern void FreeTupleDesc(TupleDesc tupdesc);
extern void IncrTupleDescRefCount(TupleDesc tupdesc);
extern void DecrTupleDescRefCount(TupleDesc tupdesc);
#define PinTupleDesc(tupdesc) \
do { \
if ((tupdesc)->tdrefcount >= 0) \
IncrTupleDescRefCount(tupdesc); \
} while (0)
#define ReleaseTupleDesc(tupdesc) \
do { \
if ((tupdesc)->tdrefcount >= 0) \
DecrTupleDescRefCount(tupdesc); \
} while (0)
extern bool equalTupleDescs(TupleDesc tupdesc1, TupleDesc tupdesc2);
extern void TupleDescInitEntry(TupleDesc desc,