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Use a private memory context to store rule information in each relcache

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entry that has rules.  This allows us to release the rule parsetrees
on relcache flush without needing a working freeObject() routine.
Formerly, the rule trees were leaked permanently at relcache flush.
Also, clean up handling of rule creation and deletion --- there was
not sufficient locking of the relation being modified, and there was
no reliable notification of other backends that a relcache reload
was needed.  Also, clean up relcache.c code so that scans of system
tables needed to load a relcache entry are done in the caller's
memory context, not in CacheMemoryContext.  This prevents any
un-pfreed memory from those scans from becoming a permanent memory
leak.
This commit is contained in:
Tom Lane
2000-06-30 07:04:23 +00:00
parent c9ec78a6b8
commit b41f4ab8c4
10 changed files with 346 additions and 517 deletions
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39
src/backend/catalog/index.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.120 2000/06/28 03:31:23 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/catalog/index.c,v 1.121 2000/06/30 07:04:17 tgl Exp $
*
*
* INTERFACE ROUTINES
@@ -369,16 +369,21 @@ ConstructTupleDescriptor(Oid heapoid,
/* ----------------------------------------------------------------
* AccessMethodObjectIdGetForm
* Returns the formated access method tuple given its object identifier.
* Returns an access method tuple given its object identifier,
* or NULL if no such AM tuple can be found.
*
* XXX ADD INDEXING
* Scanning is done using CurrentMemoryContext as working storage,
* but the returned tuple will be allocated in resultCxt (which is
* typically CacheMemoryContext).
*
* Note:
* Assumes object identifier is valid.
* There was a note here about adding indexing, but I don't see a need
* for it. There are so few tuples in pg_am that an indexscan would
* surely be slower.
* ----------------------------------------------------------------
*/
Form_pg_am
AccessMethodObjectIdGetForm(Oid accessMethodObjectId)
AccessMethodObjectIdGetForm(Oid accessMethodObjectId,
MemoryContext resultCxt)
{
Relation pg_am_desc;
HeapScanDesc pg_am_scan;
@@ -415,10 +420,10 @@ AccessMethodObjectIdGetForm(Oid accessMethodObjectId)
}
/* ----------------
* if found am tuple, then copy the form and return the copy
* if found AM tuple, then copy it into resultCxt and return the copy
* ----------------
*/
aform = (Form_pg_am) palloc(sizeof *aform);
aform = (Form_pg_am) MemoryContextAlloc(resultCxt, sizeof *aform);
memcpy(aform, GETSTRUCT(pg_am_tuple), sizeof *aform);
heap_endscan(pg_am_scan);
@@ -434,22 +439,8 @@ AccessMethodObjectIdGetForm(Oid accessMethodObjectId)
static void
ConstructIndexReldesc(Relation indexRelation, Oid amoid)
{
MemoryContext oldcxt;
/* ----------------
* here we make certain to allocate the access method
* tuple within the cache context lest it vanish when the
* context changes
* ----------------
*/
if (!CacheMemoryContext)
CreateCacheMemoryContext();
oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
indexRelation->rd_am = AccessMethodObjectIdGetForm(amoid);
MemoryContextSwitchTo(oldcxt);
indexRelation->rd_am = AccessMethodObjectIdGetForm(amoid,
CacheMemoryContext);
/* ----------------
* XXX missing the initialization of some other fields