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First cut at making indexscan cost estimates depend on correlation

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between index order and table order.
This commit is contained in:
Tom Lane
2001-05-09 23:13:37 +00:00
parent e02033572d
commit c23bc6fbb0
8 changed files with 317 additions and 88 deletions
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32
src/backend/utils/cache/lsyscache.c vendored
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.54 2001/05/09 00:35:09 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/cache/lsyscache.c,v 1.55 2001/05/09 23:13:35 tgl Exp $
*
* NOTES
* Eventually, the index information should go through here, too.
@ -185,6 +185,36 @@ get_atttypmod(Oid relid, AttrNumber attnum)
return -1;
}
/*
* get_atttypetypmod
*
* A two-fer: given the relation id and the attribute number,
* fetch both type OID and atttypmod in a single cache lookup.
*
* Unlike the otherwise-similar get_atttype/get_atttypmod, this routine
* raises an error if it can't obtain the information.
*/
void
get_atttypetypmod(Oid relid, AttrNumber attnum,
Oid *typid, int32 *typmod)
{
HeapTuple tp;
Form_pg_attribute att_tup;
tp = SearchSysCache(ATTNUM,
ObjectIdGetDatum(relid),
Int16GetDatum(attnum),
0, 0);
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for relation %u attribute %d",
relid, attnum);
att_tup = (Form_pg_attribute) GETSTRUCT(tp);
*typid = att_tup->atttypid;
*typmod = att_tup->atttypmod;
ReleaseSysCache(tp);
}
/* ---------- INDEX CACHE ---------- */
/* watch this space...