database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-12 05:01:15 +03:00
Code Activity

Add support for cross-type hashing in hash index searches and hash joins.

Browse Source 
Hashing for aggregation purposes still needs work, so it's not time to
mark any cross-type operators as hashable for general use, but these cases
work if the operators are so marked by hand in the system catalogs.
This commit is contained in:
Tom Lane
2007-01-30 01:33:36 +00:00
parent e8cd6f14a2
commit a635c08fa1
12 changed files with 240 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/backend/access/hash/hashsearch.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.47 2007/01/20 18:43:35 neilc Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashsearch.c,v 1.48 2007/01/30 01:33:36 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -115,6 +115,7 @@ _hash_first(IndexScanDesc scan, ScanDirection dir)
{
Relation rel = scan->indexRelation;
HashScanOpaque so = (HashScanOpaque) scan->opaque;
ScanKey cur;
uint32 hashkey;
Bucket bucket;
BlockNumber blkno;
@@ -143,18 +144,37 @@ _hash_first(IndexScanDesc scan, ScanDirection dir)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("hash indexes do not support whole-index scans")));
/* There may be more than one index qual, but we hash only the first */
cur = &scan->keyData[0];
/* We support only single-column hash indexes */
Assert(cur->sk_attno == 1);
/* And there's only one operator strategy, too */
Assert(cur->sk_strategy == HTEqualStrategyNumber);
/*
* If the constant in the index qual is NULL, assume it cannot match any
* items in the index.
*/
if (scan->keyData[0].sk_flags & SK_ISNULL)
if (cur->sk_flags & SK_ISNULL)
return false;
/*
* Okay to compute the hash key. We want to do this before acquiring any
* locks, in case a user-defined hash function happens to be slow.
*
* If scankey operator is not a cross-type comparison, we can use the
* cached hash function; otherwise gotta look it up in the catalogs.
*
* We support the convention that sk_subtype == InvalidOid means the
* opclass input type; this is a hack to simplify life for ScanKeyInit().
*/
hashkey = _hash_datum2hashkey(rel, scan->keyData[0].sk_argument);
if (cur->sk_subtype == rel->rd_opcintype[0] ||
cur->sk_subtype == InvalidOid)
hashkey = _hash_datum2hashkey(rel, cur->sk_argument);
else
hashkey = _hash_datum2hashkey_type(rel, cur->sk_argument,
cur->sk_subtype);
/*
* Acquire shared split lock so we can compute the target bucket safely

31
src/backend/access/hash/hashutil.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.50 2007/01/05 22:19:22 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/hash/hashutil.c,v 1.51 2007/01/30 01:33:36 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -18,6 +18,7 @@
#include "access/hash.h"
#include "access/reloptions.h"
#include "executor/execdebug.h"
#include "utils/lsyscache.h"
/*
@@ -63,6 +64,9 @@ _hash_checkqual(IndexScanDesc scan, IndexTuple itup)
/*
* _hash_datum2hashkey -- given a Datum, call the index's hash procedure
*
* The Datum is assumed to be of the index's column type, so we can use the
* "primary" hash procedure that's tracked for us by the generic index code.
*/
uint32
_hash_datum2hashkey(Relation rel, Datum key)
@@ -75,6 +79,31 @@ _hash_datum2hashkey(Relation rel, Datum key)
return DatumGetUInt32(FunctionCall1(procinfo, key));
}
/*
* _hash_datum2hashkey_type -- given a Datum of a specified type,
* hash it in a fashion compatible with this index
*
* This is much more expensive than _hash_datum2hashkey, so use it only in
* cross-type situations.
*/
uint32
_hash_datum2hashkey_type(Relation rel, Datum key, Oid keytype)
{
RegProcedure hash_proc;
/* XXX assumes index has only one attribute */
hash_proc = get_opfamily_proc(rel->rd_opfamily[0],
keytype,
keytype,
HASHPROC);
if (!RegProcedureIsValid(hash_proc))
elog(ERROR, "missing support function %d(%u,%u) for index \"%s\"",
HASHPROC, keytype, keytype,
RelationGetRelationName(rel));
return DatumGetUInt32(OidFunctionCall1(hash_proc, key));
}
/*
* _hash_hashkey2bucket -- determine which bucket the hashkey maps to.
*/