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First cut at recycling space in btree indexes. Still some rough edges

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to fix, but it seems to basically work...
This commit is contained in:
Tom Lane
2003-02-23 06:17:13 +00:00
parent 27854915b9
commit 88dc31e3f2
8 changed files with 745 additions and 32 deletions
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63
src/backend/access/nbtree/nbtree.c
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@ -12,7 +12,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.96 2003/02/22 00:45:04 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtree.c,v 1.97 2003/02/23 06:17:13 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -710,15 +710,16 @@ Datum
btvacuumcleanup(PG_FUNCTION_ARGS)
{
Relation rel = (Relation) PG_GETARG_POINTER(0);
#ifdef NOT_USED
IndexVacuumCleanupInfo *info = (IndexVacuumCleanupInfo *) PG_GETARG_POINTER(1);
#endif
IndexBulkDeleteResult *stats = (IndexBulkDeleteResult *) PG_GETARG_POINTER(2);
BlockNumber num_pages;
BlockNumber blkno;
PageFreeSpaceInfo *pageSpaces;
int nFreePages,
maxFreePages;
BlockNumber pages_deleted = 0;
MemoryContext mycontext;
MemoryContext oldcontext;
Assert(stats != NULL);
@ -731,6 +732,13 @@ btvacuumcleanup(PG_FUNCTION_ARGS)
pageSpaces = (PageFreeSpaceInfo *) palloc(maxFreePages * sizeof(PageFreeSpaceInfo));
nFreePages = 0;
/* Create a temporary memory context to run _bt_pagedel in */
mycontext = AllocSetContextCreate(CurrentMemoryContext,
"_bt_pagedel",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/*
* Scan through all pages of index, except metapage. (Any pages added
* after we start the scan will not be examined; this should be fine,
@ -745,17 +753,53 @@ btvacuumcleanup(PG_FUNCTION_ARGS)
buf = _bt_getbuf(rel, blkno, BT_READ);
page = BufferGetPage(buf);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
if (P_ISDELETED(opaque))
if (_bt_page_recyclable(page))
{
/* XXX if safe-to-reclaim... */
/* Okay to recycle this page */
if (nFreePages < maxFreePages)
{
pageSpaces[nFreePages].blkno = blkno;
/* The avail-space value is bogus, but must be < BLCKSZ */
/* claimed avail-space must be < BLCKSZ */
pageSpaces[nFreePages].avail = BLCKSZ-1;
nFreePages++;
}
}
else if ((opaque->btpo_flags & BTP_HALF_DEAD) ||
P_FIRSTDATAKEY(opaque) > PageGetMaxOffsetNumber(page))
{
/* Empty, try to delete */
int ndel;
/* Run pagedel in a temp context to avoid memory leakage */
MemoryContextReset(mycontext);
oldcontext = MemoryContextSwitchTo(mycontext);
ndel = _bt_pagedel(rel, buf, info->vacuum_full);
pages_deleted += ndel;
/*
* During VACUUM FULL it's okay to recycle deleted pages
* immediately, since there can be no other transactions
* scanning the index. Note that we will only recycle the
* current page and not any parent pages that _bt_pagedel
* might have recursed to; this seems reasonable in the name
* of simplicity. (Trying to do otherwise would mean we'd
* have to sort the list of recyclable pages we're building.)
*/
if (ndel && info->vacuum_full)
{
if (nFreePages < maxFreePages)
{
pageSpaces[nFreePages].blkno = blkno;
/* claimed avail-space must be < BLCKSZ */
pageSpaces[nFreePages].avail = BLCKSZ-1;
nFreePages++;
}
}
MemoryContextSwitchTo(oldcontext);
continue; /* pagedel released buffer */
}
_bt_relbuf(rel, buf);
}
@ -768,6 +812,13 @@ btvacuumcleanup(PG_FUNCTION_ARGS)
pfree(pageSpaces);
MemoryContextDelete(mycontext);
if (pages_deleted > 0)
elog(info->message_level, "Index %s: %u pages, deleted %u; %u now free",
RelationGetRelationName(rel),
num_pages, pages_deleted, nFreePages);
/* update statistics */
stats->num_pages = num_pages;
stats->pages_free = nFreePages;