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Reimplement hash index locking algorithms, per my recent proposal to

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pghackers.  This fixes the problem recently reported by Markus KrÌutner
(hash bucket split corrupts the state of scans being done concurrently),
and I believe it also fixes all the known problems with deadlocks in
hash index operations.  Hash indexes are still not really ready for prime
time (since they aren't WAL-logged), but this is a step forward.
This commit is contained in:
Tom Lane
2003-09-04 22:06:27 +00:00
parent ca43f71ca5
commit 7a3693716d
11 changed files with 1052 additions and 1036 deletions
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71
src/backend/access/hash/hashutil.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/hash/hashutil.c,v 1.35 2003/09/02 18:13:31 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/hash/hashutil.c,v 1.36 2003/09/04 22:06:27 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -19,46 +19,6 @@
#include "access/iqual.h"
/*
* _hash_mkscankey -- build a scan key matching the given indextuple
*
* Note: this is prepared for multiple index columns, but very little
* else in access/hash is ...
*/
ScanKey
_hash_mkscankey(Relation rel, IndexTuple itup)
{
ScanKey skey;
TupleDesc itupdesc = RelationGetDescr(rel);
int natts = rel->rd_rel->relnatts;
AttrNumber i;
Datum arg;
FmgrInfo *procinfo;
bool isnull;
skey = (ScanKey) palloc(natts * sizeof(ScanKeyData));
for (i = 0; i < natts; i++)
{
arg = index_getattr(itup, i + 1, itupdesc, &isnull);
procinfo = index_getprocinfo(rel, i + 1, HASHPROC);
ScanKeyEntryInitializeWithInfo(&skey[i],
isnull ? SK_ISNULL : 0x0,
(AttrNumber) (i + 1),
procinfo,
CurrentMemoryContext,
arg);
}
return skey;
}
void
_hash_freeskey(ScanKey skey)
{
pfree(skey);
}
/*
* _hash_checkqual -- does the index tuple satisfy the scan conditions?
*/
@@ -102,24 +62,31 @@ _hash_formitem(IndexTuple itup)
}
/*
* _hash_call -- given a Datum, call the index's hash procedure
*
* Returns the bucket number that the hash key maps to.
* _hash_datum2hashkey -- given a Datum, call the index's hash procedure
*/
Bucket
_hash_call(Relation rel, HashMetaPage metap, Datum key)
uint32
_hash_datum2hashkey(Relation rel, Datum key)
{
FmgrInfo *procinfo;
uint32 n;
Bucket bucket;
/* XXX assumes index has only one attribute */
procinfo = index_getprocinfo(rel, 1, HASHPROC);
n = DatumGetUInt32(FunctionCall1(procinfo, key));
bucket = n & metap->hashm_highmask;
if (bucket > metap->hashm_maxbucket)
bucket = bucket & metap->hashm_lowmask;
return DatumGetUInt32(FunctionCall1(procinfo, key));
}
/*
* _hash_hashkey2bucket -- determine which bucket the hashkey maps to.
*/
Bucket
_hash_hashkey2bucket(uint32 hashkey, uint32 maxbucket,
uint32 highmask, uint32 lowmask)
{
Bucket bucket;
bucket = hashkey & highmask;
if (bucket > maxbucket)
bucket = bucket & lowmask;
return bucket;
}