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Tweak hash index AM to use the new ReadOrZeroBuffer bufmgr API when fetching

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pages it intends to zero immediately.  Just to show there is some use for that
function besides WAL recovery :-).
Along the way, fold _hash_checkpage and _hash_pageinit calls into _hash_getbuf
and friends, instead of expecting callers to do that separately.
REL8_3_STABLE
Tom Lane 18 years ago
parent 1aefa0489f
commit 0fef38da21
8 changed files with 110 additions and 85 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 4
      contrib/pgstattuple/pgstattuple.c
  2. 12
      src/backend/access/hash/hash.c
  3. 12
      src/backend/access/hash/hashinsert.c
  4. 54
      src/backend/access/hash/hashovfl.c
  5. 85
      src/backend/access/hash/hashpage.c
  6. 15
      src/backend/access/hash/hashsearch.c
  7. 5
      src/backend/access/hash/hashutil.c
  8. 8
      src/include/access/hash.h

4
contrib/pgstattuple/pgstattuple.c
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@ -1,5 +1,5 @@
/*
* $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.26 2007/03/25 19:45:13 tgl Exp $
* $PostgreSQL: pgsql/contrib/pgstattuple/pgstattuple.c,v 1.27 2007/05/03 16:45:58 tgl Exp $
*
* Copyright (c) 2001,2002 Tatsuo Ishii
*
@ -360,7 +360,7 @@ pgstat_hash_page(pgstattuple_type * stat, Relation rel, BlockNumber blkno)
Page page;
_hash_getlock(rel, blkno, HASH_SHARE);
buf = _hash_getbuf(rel, blkno, HASH_READ);
buf = _hash_getbuf(rel, blkno, HASH_READ, 0);
page = BufferGetPage(buf);
if (PageGetSpecialSize(page) == MAXALIGN(sizeof(HashPageOpaqueData)))

12
src/backend/access/hash/hash.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.93 2007/01/20 18:43:35 neilc Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hash.c,v 1.94 2007/05/03 16:45:58 tgl Exp $
*
* NOTES
* This file contains only the public interface routines.
@ -506,8 +506,7 @@ hashbulkdelete(PG_FUNCTION_ARGS)
* array cannot change under us; and it beats rereading the metapage for
* each bucket.
*/
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ);
_hash_checkpage(rel, metabuf, LH_META_PAGE);
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
metap = (HashMetaPage) BufferGetPage(metabuf);
orig_maxbucket = metap->hashm_maxbucket;
orig_ntuples = metap->hashm_ntuples;
@ -548,8 +547,8 @@ loop_top:
vacuum_delay_point();
buf = _hash_getbuf(rel, blkno, HASH_WRITE);
_hash_checkpage(rel, buf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
buf = _hash_getbuf(rel, blkno, HASH_WRITE,
LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
page = BufferGetPage(buf);
opaque = (HashPageOpaque) PageGetSpecialPointer(page);
Assert(opaque->hasho_bucket == cur_bucket);
@ -607,8 +606,7 @@ loop_top:
}
/* Write-lock metapage and check for split since we started */
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_WRITE);
_hash_checkpage(rel, metabuf, LH_META_PAGE);
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_WRITE, LH_META_PAGE);
metap = (HashMetaPage) BufferGetPage(metabuf);
if (cur_maxbucket != metap->hashm_maxbucket)

12
src/backend/access/hash/hashinsert.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashinsert.c,v 1.44 2007/01/05 22:19:22 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashinsert.c,v 1.45 2007/05/03 16:45:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -66,8 +66,7 @@ _hash_doinsert(Relation rel, IndexTuple itup)
_hash_getlock(rel, 0, HASH_SHARE);
/* Read the metapage */
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ);
_hash_checkpage(rel, metabuf, LH_META_PAGE);
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
metap = (HashMetaPage) BufferGetPage(metabuf);
/*
@ -104,8 +103,7 @@ _hash_doinsert(Relation rel, IndexTuple itup)
_hash_droplock(rel, 0, HASH_SHARE);
/* Fetch the primary bucket page for the bucket */
buf = _hash_getbuf(rel, blkno, HASH_WRITE);
_hash_checkpage(rel, buf, LH_BUCKET_PAGE);
buf = _hash_getbuf(rel, blkno, HASH_WRITE, LH_BUCKET_PAGE);
page = BufferGetPage(buf);
pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
Assert(pageopaque->hasho_bucket == bucket);
@ -125,7 +123,7 @@ _hash_doinsert(Relation rel, IndexTuple itup)
* find out next pass through the loop test above.
*/
_hash_relbuf(rel, buf);
buf = _hash_getbuf(rel, nextblkno, HASH_WRITE);
buf = _hash_getbuf(rel, nextblkno, HASH_WRITE, LH_OVERFLOW_PAGE);
page = BufferGetPage(buf);
}
else
@ -145,8 +143,8 @@ _hash_doinsert(Relation rel, IndexTuple itup)
/* should fit now, given test above */
Assert(PageGetFreeSpace(page) >= itemsz);
}
_hash_checkpage(rel, buf, LH_OVERFLOW_PAGE);
pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
Assert(pageopaque->hasho_flag == LH_OVERFLOW_PAGE);
Assert(pageopaque->hasho_bucket == bucket);
}

54
src/backend/access/hash/hashovfl.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashovfl.c,v 1.56 2007/04/19 20:24:04 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashovfl.c,v 1.57 2007/05/03 16:45:58 tgl Exp $
*
* NOTES
* Overflow pages look like ordinary relation pages.
@ -107,7 +107,6 @@ _hash_addovflpage(Relation rel, Buffer metabuf, Buffer buf)
/* allocate and lock an empty overflow page */
ovflbuf = _hash_getovflpage(rel, metabuf);
ovflpage = BufferGetPage(ovflbuf);
/*
* Write-lock the tail page. It is okay to hold two buffer locks here
@ -115,12 +114,14 @@ _hash_addovflpage(Relation rel, Buffer metabuf, Buffer buf)
*/
_hash_chgbufaccess(rel, buf, HASH_NOLOCK, HASH_WRITE);
/* probably redundant... */
_hash_checkpage(rel, buf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
/* loop to find current tail page, in case someone else inserted too */
for (;;)
{
BlockNumber nextblkno;
_hash_checkpage(rel, buf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
page = BufferGetPage(buf);
pageopaque = (HashPageOpaque) PageGetSpecialPointer(page);
nextblkno = pageopaque->hasho_nextblkno;
@ -131,11 +132,11 @@ _hash_addovflpage(Relation rel, Buffer metabuf, Buffer buf)
/* we assume we do not need to write the unmodified page */
_hash_relbuf(rel, buf);
buf = _hash_getbuf(rel, nextblkno, HASH_WRITE);
buf = _hash_getbuf(rel, nextblkno, HASH_WRITE, LH_OVERFLOW_PAGE);
}
/* now that we have correct backlink, initialize new overflow page */
_hash_pageinit(ovflpage, BufferGetPageSize(ovflbuf));
ovflpage = BufferGetPage(ovflbuf);
ovflopaque = (HashPageOpaque) PageGetSpecialPointer(ovflpage);
ovflopaque->hasho_prevblkno = BufferGetBlockNumber(buf);
ovflopaque->hasho_nextblkno = InvalidBlockNumber;
@ -156,7 +157,8 @@ _hash_addovflpage(Relation rel, Buffer metabuf, Buffer buf)
* _hash_getovflpage()
*
* Find an available overflow page and return it. The returned buffer
* is pinned and write-locked, but its contents are not initialized.
* is pinned and write-locked, and has had _hash_pageinit() applied,
* but it is caller's responsibility to fill the special space.
*
* The caller must hold a pin, but no lock, on the metapage buffer.
* That buffer is left in the same state at exit.
@ -220,8 +222,7 @@ _hash_getovflpage(Relation rel, Buffer metabuf)
/* Release exclusive lock on metapage while reading bitmap page */
_hash_chgbufaccess(rel, metabuf, HASH_READ, HASH_NOLOCK);
mapbuf = _hash_getbuf(rel, mapblkno, HASH_WRITE);
_hash_checkpage(rel, mapbuf, LH_BITMAP_PAGE);
mapbuf = _hash_getbuf(rel, mapblkno, HASH_WRITE, LH_BITMAP_PAGE);
mappage = BufferGetPage(mapbuf);
freep = HashPageGetBitmap(mappage);
@ -277,7 +278,7 @@ _hash_getovflpage(Relation rel, Buffer metabuf)
* with metapage write lock held; would be better to use a lock that
* doesn't block incoming searches.
*/
newbuf = _hash_getnewbuf(rel, blkno, HASH_WRITE);
newbuf = _hash_getnewbuf(rel, blkno);
metap->hashm_spares[splitnum]++;
@ -327,8 +328,8 @@ found:
_hash_chgbufaccess(rel, metabuf, HASH_READ, HASH_NOLOCK);
}
/* Fetch and return the recycled page */
return _hash_getbuf(rel, blkno, HASH_WRITE);
/* Fetch, init, and return the recycled page */
return _hash_getinitbuf(rel, blkno);
}
/*
@ -412,30 +413,29 @@ _hash_freeovflpage(Relation rel, Buffer ovflbuf)
*/
if (BlockNumberIsValid(prevblkno))
{
Buffer prevbuf = _hash_getbuf(rel, prevblkno, HASH_WRITE);
Buffer prevbuf = _hash_getbuf(rel, prevblkno, HASH_WRITE,
LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
Page prevpage = BufferGetPage(prevbuf);
HashPageOpaque prevopaque = (HashPageOpaque) PageGetSpecialPointer(prevpage);
_hash_checkpage(rel, prevbuf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
Assert(prevopaque->hasho_bucket == bucket);
prevopaque->hasho_nextblkno = nextblkno;
_hash_wrtbuf(rel, prevbuf);
}
if (BlockNumberIsValid(nextblkno))
{
Buffer nextbuf = _hash_getbuf(rel, nextblkno, HASH_WRITE);
Buffer nextbuf = _hash_getbuf(rel, nextblkno, HASH_WRITE,
LH_OVERFLOW_PAGE);
Page nextpage = BufferGetPage(nextbuf);
HashPageOpaque nextopaque = (HashPageOpaque) PageGetSpecialPointer(nextpage);
_hash_checkpage(rel, nextbuf, LH_OVERFLOW_PAGE);
Assert(nextopaque->hasho_bucket == bucket);
nextopaque->hasho_prevblkno = prevblkno;
_hash_wrtbuf(rel, nextbuf);
}
/* Read the metapage so we can determine which bitmap page to use */
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ);
_hash_checkpage(rel, metabuf, LH_META_PAGE);
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
metap = (HashMetaPage) BufferGetPage(metabuf);
/* Identify which bit to set */
@ -452,8 +452,7 @@ _hash_freeovflpage(Relation rel, Buffer ovflbuf)
_hash_chgbufaccess(rel, metabuf, HASH_READ, HASH_NOLOCK);
/* Clear the bitmap bit to indicate that this overflow page is free */
mapbuf = _hash_getbuf(rel, blkno, HASH_WRITE);
_hash_checkpage(rel, mapbuf, LH_BITMAP_PAGE);
mapbuf = _hash_getbuf(rel, blkno, HASH_WRITE, LH_BITMAP_PAGE);
mappage = BufferGetPage(mapbuf);
freep = HashPageGetBitmap(mappage);
Assert(ISSET(freep, bitmapbit));
@ -507,11 +506,10 @@ _hash_initbitmap(Relation rel, HashMetaPage metap, BlockNumber blkno)
* page while holding the metapage lock, but this path is taken so seldom
* that it's not worth worrying about.
*/
buf = _hash_getnewbuf(rel, blkno, HASH_WRITE);
buf = _hash_getnewbuf(rel, blkno);
pg = BufferGetPage(buf);
/* initialize the page */
_hash_pageinit(pg, BufferGetPageSize(buf));
/* initialize the page's special space */
op = (HashPageOpaque) PageGetSpecialPointer(pg);
op->hasho_prevblkno = InvalidBlockNumber;
op->hasho_nextblkno = InvalidBlockNumber;
@ -583,8 +581,7 @@ _hash_squeezebucket(Relation rel,
* start squeezing into the base bucket page.
*/
wblkno = bucket_blkno;
wbuf = _hash_getbuf(rel, wblkno, HASH_WRITE);
_hash_checkpage(rel, wbuf, LH_BUCKET_PAGE);
wbuf = _hash_getbuf(rel, wblkno, HASH_WRITE, LH_BUCKET_PAGE);
wpage = BufferGetPage(wbuf);
wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);
@ -607,8 +604,7 @@ _hash_squeezebucket(Relation rel,
rblkno = ropaque->hasho_nextblkno;
if (ropaque != wopaque)
_hash_relbuf(rel, rbuf);
rbuf = _hash_getbuf(rel, rblkno, HASH_WRITE);
_hash_checkpage(rel, rbuf, LH_OVERFLOW_PAGE);
rbuf = _hash_getbuf(rel, rblkno, HASH_WRITE, LH_OVERFLOW_PAGE);
rpage = BufferGetPage(rbuf);
ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
Assert(ropaque->hasho_bucket == bucket);
@ -648,8 +644,7 @@ _hash_squeezebucket(Relation rel,
return;
}
wbuf = _hash_getbuf(rel, wblkno, HASH_WRITE);
_hash_checkpage(rel, wbuf, LH_OVERFLOW_PAGE);
wbuf = _hash_getbuf(rel, wblkno, HASH_WRITE, LH_OVERFLOW_PAGE);
wpage = BufferGetPage(wbuf);
wopaque = (HashPageOpaque) PageGetSpecialPointer(wpage);
Assert(wopaque->hasho_bucket == bucket);
@ -701,8 +696,7 @@ _hash_squeezebucket(Relation rel,
/* free this overflow page, then get the previous one */
_hash_freeovflpage(rel, rbuf);
rbuf = _hash_getbuf(rel, rblkno, HASH_WRITE);
_hash_checkpage(rel, rbuf, LH_OVERFLOW_PAGE);
rbuf = _hash_getbuf(rel, rblkno, HASH_WRITE, LH_OVERFLOW_PAGE);
rpage = BufferGetPage(rbuf);
ropaque = (HashPageOpaque) PageGetSpecialPointer(rpage);
Assert(ropaque->hasho_bucket == bucket);

85
src/backend/access/hash/hashpage.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashpage.c,v 1.66 2007/04/19 20:24:04 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashpage.c,v 1.67 2007/05/03 16:45:58 tgl Exp $
*
* NOTES
* Postgres hash pages look like ordinary relation pages. The opaque
@ -100,21 +100,21 @@ _hash_droplock(Relation rel, BlockNumber whichlock, int access)
* _hash_getbuf() -- Get a buffer by block number for read or write.
*
* 'access' must be HASH_READ, HASH_WRITE, or HASH_NOLOCK.
* 'flags' is a bitwise OR of the allowed page types.
*
* This must be used only to fetch pages that are expected to be valid
* already. _hash_checkpage() is applied using the given flags.
*
* When this routine returns, the appropriate lock is set on the
* requested buffer and its reference count has been incremented
* (ie, the buffer is "locked and pinned").
*
* P_NEW is disallowed because this routine should only be used
* P_NEW is disallowed because this routine can only be used
* to access pages that are known to be before the filesystem EOF.
* Extending the index should be done with _hash_getnewbuf.
*
* All call sites should call either _hash_checkpage or _hash_pageinit
* on the returned page, depending on whether the block is expected
* to be valid or not.
*/
Buffer
_hash_getbuf(Relation rel, BlockNumber blkno, int access)
_hash_getbuf(Relation rel, BlockNumber blkno, int access, int flags)
{
Buffer buf;
@ -127,13 +127,52 @@ _hash_getbuf(Relation rel, BlockNumber blkno, int access)
LockBuffer(buf, access);
/* ref count and lock type are correct */
_hash_checkpage(rel, buf, flags);
return buf;
}
/*
* _hash_getinitbuf() -- Get and initialize a buffer by block number.
*
* This must be used only to fetch pages that are known to be before
* the index's filesystem EOF, but are to be filled from scratch.
* _hash_pageinit() is applied automatically. Otherwise it has
* effects similar to _hash_getbuf() with access = HASH_WRITE.
*
* When this routine returns, a write lock is set on the
* requested buffer and its reference count has been incremented
* (ie, the buffer is "locked and pinned").
*
* P_NEW is disallowed because this routine can only be used
* to access pages that are known to be before the filesystem EOF.
* Extending the index should be done with _hash_getnewbuf.
*/
Buffer
_hash_getinitbuf(Relation rel, BlockNumber blkno)
{
Buffer buf;
if (blkno == P_NEW)
elog(ERROR, "hash AM does not use P_NEW");
buf = ReadOrZeroBuffer(rel, blkno);
LockBuffer(buf, HASH_WRITE);
/* ref count and lock type are correct */
/* initialize the page */
_hash_pageinit(BufferGetPage(buf), BufferGetPageSize(buf));
return buf;
}
/*
* _hash_getnewbuf() -- Get a new page at the end of the index.
*
* This has the same API as _hash_getbuf, except that we are adding
* This has the same API as _hash_getinitbuf, except that we are adding
* a page to the index, and hence expect the page to be past the
* logical EOF. (However, we have to support the case where it isn't,
* since a prior try might have crashed after extending the filesystem
@ -141,12 +180,9 @@ _hash_getbuf(Relation rel, BlockNumber blkno, int access)
*
* It is caller's responsibility to ensure that only one process can
* extend the index at a time.
*
* All call sites should call _hash_pageinit on the returned page.
* Also, it's difficult to imagine why access would not be HASH_WRITE.
*/
Buffer
_hash_getnewbuf(Relation rel, BlockNumber blkno, int access)
_hash_getnewbuf(Relation rel, BlockNumber blkno)
{
BlockNumber nblocks = RelationGetNumberOfBlocks(rel);
Buffer buf;
@ -166,12 +202,15 @@ _hash_getnewbuf(Relation rel, BlockNumber blkno, int access)
BufferGetBlockNumber(buf), blkno);
}
else
buf = ReadBuffer(rel, blkno);
buf = ReadOrZeroBuffer(rel, blkno);
if (access != HASH_NOLOCK)
LockBuffer(buf, access);
LockBuffer(buf, HASH_WRITE);
/* ref count and lock type are correct */
/* initialize the page */
_hash_pageinit(BufferGetPage(buf), BufferGetPageSize(buf));
return buf;
}
@ -292,9 +331,8 @@ _hash_metapinit(Relation rel)
* smgrextend() calls to occur. This ensures that the smgr level
* has the right idea of the physical index length.
*/
metabuf = _hash_getnewbuf(rel, HASH_METAPAGE, HASH_WRITE);
metabuf = _hash_getnewbuf(rel, HASH_METAPAGE);
pg = BufferGetPage(metabuf);
_hash_pageinit(pg, BufferGetPageSize(metabuf));
pageopaque = (HashPageOpaque) PageGetSpecialPointer(pg);
pageopaque->hasho_prevblkno = InvalidBlockNumber;
@ -350,9 +388,8 @@ _hash_metapinit(Relation rel)
*/
for (i = 0; i <= 1; i++)
{
buf = _hash_getnewbuf(rel, BUCKET_TO_BLKNO(metap, i), HASH_WRITE);
buf = _hash_getnewbuf(rel, BUCKET_TO_BLKNO(metap, i));
pg = BufferGetPage(buf);
_hash_pageinit(pg, BufferGetPageSize(buf));
pageopaque = (HashPageOpaque) PageGetSpecialPointer(pg);
pageopaque->hasho_prevblkno = InvalidBlockNumber;
pageopaque->hasho_nextblkno = InvalidBlockNumber;
@ -679,17 +716,15 @@ _hash_splitbucket(Relation rel,
* either bucket.
*/
oblkno = start_oblkno;
obuf = _hash_getbuf(rel, oblkno, HASH_WRITE);
_hash_checkpage(rel, obuf, LH_BUCKET_PAGE);
obuf = _hash_getbuf(rel, oblkno, HASH_WRITE, LH_BUCKET_PAGE);
opage = BufferGetPage(obuf);
oopaque = (HashPageOpaque) PageGetSpecialPointer(opage);
nblkno = start_nblkno;
nbuf = _hash_getbuf(rel, nblkno, HASH_WRITE);
nbuf = _hash_getnewbuf(rel, nblkno);
npage = BufferGetPage(nbuf);
/* initialize the new bucket's primary page */
_hash_pageinit(npage, BufferGetPageSize(nbuf));
nopaque = (HashPageOpaque) PageGetSpecialPointer(npage);
nopaque->hasho_prevblkno = InvalidBlockNumber;
nopaque->hasho_nextblkno = InvalidBlockNumber;
@ -725,8 +760,7 @@ _hash_splitbucket(Relation rel,
*/
_hash_wrtbuf(rel, obuf);
obuf = _hash_getbuf(rel, oblkno, HASH_WRITE);
_hash_checkpage(rel, obuf, LH_OVERFLOW_PAGE);
obuf = _hash_getbuf(rel, oblkno, HASH_WRITE, LH_OVERFLOW_PAGE);
opage = BufferGetPage(obuf);
oopaque = (HashPageOpaque) PageGetSpecialPointer(opage);
ooffnum = FirstOffsetNumber;
@ -763,7 +797,6 @@ _hash_splitbucket(Relation rel,
_hash_chgbufaccess(rel, nbuf, HASH_WRITE, HASH_NOLOCK);
/* chain to a new overflow page */
nbuf = _hash_addovflpage(rel, metabuf, nbuf);
_hash_checkpage(rel, nbuf, LH_OVERFLOW_PAGE);
npage = BufferGetPage(nbuf);
/* we don't need nopaque within the loop */
}

15
src/backend/access/hash/hashsearch.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.48 2007/01/30 01:33:36 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.49 2007/05/03 16:45:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -73,8 +73,7 @@ _hash_readnext(Relation rel,
*bufp = InvalidBuffer;
if (BlockNumberIsValid(blkno))
{
*bufp = _hash_getbuf(rel, blkno, HASH_READ);
_hash_checkpage(rel, *bufp, LH_OVERFLOW_PAGE);
*bufp = _hash_getbuf(rel, blkno, HASH_READ, LH_OVERFLOW_PAGE);
*pagep = BufferGetPage(*bufp);
*opaquep = (HashPageOpaque) PageGetSpecialPointer(*pagep);
}
@ -94,8 +93,8 @@ _hash_readprev(Relation rel,
*bufp = InvalidBuffer;
if (BlockNumberIsValid(blkno))
{
*bufp = _hash_getbuf(rel, blkno, HASH_READ);
_hash_checkpage(rel, *bufp, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
*bufp = _hash_getbuf(rel, blkno, HASH_READ,
LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
*pagep = BufferGetPage(*bufp);
*opaquep = (HashPageOpaque) PageGetSpecialPointer(*pagep);
}
@ -183,8 +182,7 @@ _hash_first(IndexScanDesc scan, ScanDirection dir)
_hash_getlock(rel, 0, HASH_SHARE);
/* Read the metapage */
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ);
_hash_checkpage(rel, metabuf, LH_META_PAGE);
metabuf = _hash_getbuf(rel, HASH_METAPAGE, HASH_READ, LH_META_PAGE);
metap = (HashMetaPage) BufferGetPage(metabuf);
/*
@ -213,8 +211,7 @@ _hash_first(IndexScanDesc scan, ScanDirection dir)
so->hashso_bucket_blkno = blkno;
/* Fetch the primary bucket page for the bucket */
buf = _hash_getbuf(rel, blkno, HASH_READ);
_hash_checkpage(rel, buf, LH_BUCKET_PAGE);
buf = _hash_getbuf(rel, blkno, HASH_READ, LH_BUCKET_PAGE);
page = BufferGetPage(buf);
opaque = (HashPageOpaque) PageGetSpecialPointer(page);
Assert(opaque->hasho_bucket == bucket);

5
src/backend/access/hash/hashutil.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.51 2007/01/30 01:33:36 tgl Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.52 2007/05/03 16:45:58 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -137,6 +137,9 @@ _hash_log2(uint32 num)
/*
* _hash_checkpage -- sanity checks on the format of all hash pages
*
* If flags is not zero, it is a bitwise OR of the acceptable values of
* hasho_flag.
*/
void
_hash_checkpage(Relation rel, Buffer buf, int flags)

8
src/include/access/hash.h
Unescape View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/access/hash.h,v 1.79 2007/04/19 20:24:04 tgl Exp $
* $PostgreSQL: pgsql/src/include/access/hash.h,v 1.80 2007/05/03 16:45:58 tgl Exp $
*
* NOTES
* modeled after Margo Seltzer's hash implementation for unix.
@ -283,8 +283,10 @@ extern void _hash_squeezebucket(Relation rel,
extern void _hash_getlock(Relation rel, BlockNumber whichlock, int access);
extern bool _hash_try_getlock(Relation rel, BlockNumber whichlock, int access);
extern void _hash_droplock(Relation rel, BlockNumber whichlock, int access);
extern Buffer _hash_getbuf(Relation rel, BlockNumber blkno, int access);
extern Buffer _hash_getnewbuf(Relation rel, BlockNumber blkno, int access);
extern Buffer _hash_getbuf(Relation rel, BlockNumber blkno,
int access, int flags);
extern Buffer _hash_getinitbuf(Relation rel, BlockNumber blkno);
extern Buffer _hash_getnewbuf(Relation rel, BlockNumber blkno);
extern void _hash_relbuf(Relation rel, Buffer buf);
extern void _hash_dropbuf(Relation rel, Buffer buf);
extern void _hash_wrtbuf(Relation rel, Buffer buf);

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