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Several changes here, not very related but touching some of the same files.

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* Buffer refcount cleanup (per my "progress report" to pghackers, 9/22).
* Add links to backend PROC structs to sinval's array of per-backend info,
and use these links for routines that need to check the state of all
backends (rather than the slow, complicated search of the ShmemIndex
hashtable that was used before).  Add databaseOID to PROC structs.
* Use this to implement an interlock that prevents DESTROY DATABASE of
a database containing running backends.  (It's a little tricky to prevent
a concurrently-starting backend from getting in there, since the new
backend is not able to lock anything at the time it tries to look up
its database in pg_database.  My solution is to recheck that the DB is
OK at the end of InitPostgres.  It may not be a 100% solution, but it's
a lot better than no interlock at all...)
* In ALTER TABLE RENAME, flush buffers for the relation before doing the
rename of the physical files, to ensure we don't get failures later from
mdblindwrt().
* Update TRUNCATE patch so that it actually compiles against current
sources :-(.
You should do "make clean all" after pulling these changes.
This commit is contained in:
Tom Lane
1999-09-24 00:25:33 +00:00
parent ad791c1d14
commit e812458b27
43 changed files with 1194 additions and 931 deletions
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36
src/backend/access/heap/heapam.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.54 1999/09/18 19:05:58 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.55 1999/09/24 00:23:54 tgl Exp $
*
*
* INTERFACE ROUTINES
@ -160,7 +160,7 @@ unpinscan(HeapScanDesc scan)
ReleaseBuffer(scan->rs_pbuf);
/* ------------------------------------
* Scan will pin buffer one for each non-NULL tuple pointer
* Scan will pin buffer once for each non-NULL tuple pointer
* (ptup, ctup, ntup), so they have to be unpinned multiple
* times.
* ------------------------------------
@ -170,6 +170,10 @@ unpinscan(HeapScanDesc scan)
if (BufferIsValid(scan->rs_nbuf))
ReleaseBuffer(scan->rs_nbuf);
/* we don't bother to clear rs_pbuf etc --- caller must
* reinitialize them if scan descriptor is not being deleted.
*/
}
/* ------------------------------------------
@ -826,6 +830,8 @@ heap_getnext(HeapScanDesc scandesc, int backw)
{
if (BufferIsValid(scan->rs_nbuf))
ReleaseBuffer(scan->rs_nbuf);
scan->rs_ntup.t_data = NULL;
scan->rs_nbuf = UnknownBuffer;
return NULL;
}
@ -906,6 +912,8 @@ heap_getnext(HeapScanDesc scandesc, int backw)
{
if (BufferIsValid(scan->rs_pbuf))
ReleaseBuffer(scan->rs_pbuf);
scan->rs_ptup.t_data = NULL;
scan->rs_pbuf = UnknownBuffer;
HEAPDEBUG_3; /* heap_getnext returns NULL at end */
return NULL;
}
@ -1014,8 +1022,6 @@ heap_fetch(Relation relation,
ItemPointer tid = &(tuple->t_self);
OffsetNumber offnum;
AssertMacro(PointerIsValid(userbuf)); /* see comments above */
/* ----------------
* increment access statistics
* ----------------
@ -1067,21 +1073,17 @@ heap_fetch(Relation relation,
if (tuple->t_data == NULL)
{
/* Tuple failed time check, so we can release now. */
ReleaseBuffer(buffer);
return;
*userbuf = InvalidBuffer;
}
else
{
/* All checks passed, so return the tuple as valid.
* Caller is now responsible for releasing the buffer.
*/
*userbuf = buffer;
}
/* ----------------
* all checks passed, now either return a copy of the tuple
* or pin the buffer page and return a pointer, depending on
* whether caller gave us a valid buf.
* ----------------
*/
*userbuf = buffer; /* user is required to ReleaseBuffer()
* this */
return;
}
/* ----------------