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* Hack for non-functional btree npages estimation: 

* npages = index_pages * selectivity_of_1st_attr_clause(s)
This commit is contained in:
Vadim B. Mikheev 1997-04-24 16:07:14 +00:00
parent 72d271177c
commit 67712200f1
1 changed files with 34 additions and 7 deletions
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41
src/backend/optimizer/util/plancat.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.5 1997/04/09 01:52:04 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.6 1997/04/24 16:07:14 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -499,6 +499,8 @@ IndexSelectivity(Oid indexrelid,
float64data npages, select;
float64 amopnpages, amopselect;
Oid relam;
bool nphack = false;
float64data fattr_select = 1.0;
indRel = SearchSysCacheTuple(RELOID,
ObjectIdGetDatum(indexrelid),
@ -515,6 +517,15 @@ IndexSelectivity(Oid indexrelid,
elog(WARN, "IndexSelectivity: index %d not found",
indexrelid);
index = (IndexTupleForm)GETSTRUCT(indexTuple);
/*
* Hack for non-functional btree npages estimation:
* npages = index_pages * selectivity_of_1st_attr_clause(s)
* - vadim 04/24/97
*/
if ( relam == BTREE_AM_OID &&
varAttributeNumbers[0] != InvalidAttrNumber )
nphack = true;
npages = 0.0;
select = 1.0;
@ -556,7 +567,10 @@ IndexSelectivity(Oid indexrelid,
elog(WARN, "IndexSelectivity: no amop %d %d",
indclass, operatorObjectIds[n]);
amop = (Form_pg_amop)GETSTRUCT(amopTuple);
amopnpages = (float64) fmgr(amop->amopnpages,
if ( !nphack )
{
amopnpages = (float64) fmgr(amop->amopnpages,
(char *) operatorObjectIds[n],
(char *) indrelid,
(char *) varAttributeNumbers[n],
@ -573,8 +587,9 @@ IndexSelectivity(Oid indexrelid,
if ((i = npages) < npages) /* ceil(npages)? */
npages += 1.0;
#endif
npages += PointerIsValid(amopnpages) ? *amopnpages : 0.0;
npages += PointerIsValid(amopnpages) ? *amopnpages : 0.0;
}
amopselect = (float64) fmgr(amop->amopselect,
(char *) operatorObjectIds[n],
(char *) indrelid,
@ -583,15 +598,27 @@ IndexSelectivity(Oid indexrelid,
(char *) constFlags[n],
(char *) nIndexKeys,
(char *) indexrelid);
if ( nphack && varAttributeNumbers[n] == index->indkey[0] )
fattr_select *= PointerIsValid(amopselect) ? *amopselect : 1.0;
select *= PointerIsValid(amopselect) ? *amopselect : 1.0;
}
/*
* Estimation of npages below is hack of course, but it's
* better than it was before. - vadim 04/09/97
*/
if ( nIndexKeys > 1 )
npages = npages / (1.0 + nIndexKeys);
*idxPages = ceil ((double)(npages/nIndexKeys));
if ( nphack )
{
npages = fattr_select * ((Form_pg_class)GETSTRUCT(indRel))->relpages;
*idxPages = ceil ((double)npages);
}
else
{
if ( nIndexKeys > 1 )
npages = npages / (1.0 + nIndexKeys);
*idxPages = ceil ((double)(npages/nIndexKeys));
}
*idxSelec = select;
}