database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-08 11:42:09 +03:00
Code Activity

Improve planning of OR indexscan plans: for quals like

Browse Source 
WHERE (a = 1 or a = 2) and b = 42
and an index on (a,b), include the clause b = 42 in the indexquals
generated for each arm of the OR clause.  Essentially this is an index-
driven conversion from CNF to DNF.  Implementation is a bit klugy, but
better than not exploiting the extra quals at all ...
This commit is contained in:
Tom Lane
2001-06-05 17:13:52 +00:00
parent 7c579fa12d
commit cdd230d628
4 changed files with 87 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
src/backend/optimizer/path/orindxpath.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/orindxpath.c,v 1.43 2001/05/20 20:28:18 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/orindxpath.c,v 1.44 2001/06/05 17:13:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -38,20 +38,17 @@ static void best_or_subclause_index(Query *root, RelOptInfo *rel,
* create_index_paths() must already have been called.
*
* 'rel' is the relation entry for which the paths are to be created
* 'clauses' is the list of available restriction clause nodes
*
* Returns nothing, but adds paths to rel->pathlist via add_path().
*/
void
create_or_index_paths(Query *root,
RelOptInfo *rel,
List *clauses)
create_or_index_paths(Query *root, RelOptInfo *rel)
{
List *clist;
List *rlist;
foreach(clist, clauses)
foreach(rlist, rel->baserestrictinfo)
{
RestrictInfo *clausenode = (RestrictInfo *) lfirst(clist);
RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(rlist);
/*
* Check to see if this clause is an 'or' clause, and, if so,
@ -59,13 +56,13 @@ create_or_index_paths(Query *root,
* has been matched by an index. The information used was saved
* by create_index_paths().
*/
if (restriction_is_or_clause(clausenode) &&
clausenode->subclauseindices)
if (restriction_is_or_clause(restrictinfo) &&
restrictinfo->subclauseindices)
{
bool all_indexable = true;
List *temp;
foreach(temp, clausenode->subclauseindices)
foreach(temp, restrictinfo->subclauseindices)
{
if (lfirst(temp) == NIL)
{
@ -75,7 +72,6 @@ create_or_index_paths(Query *root,
}
if (all_indexable)
{
/*
* OK, build an IndexPath for this OR clause, using the
* best available index for each subclause.
@ -93,10 +89,7 @@ create_or_index_paths(Query *root,
*/
pathnode->path.pathkeys = NIL;
/*
* We don't actually care what order the index scans in
* ...
*/
/* We don't actually care what order the index scans in. */
pathnode->indexscandir = NoMovementScanDirection;
/* This isn't a nestloop innerjoin, so: */
@ -106,8 +99,8 @@ create_or_index_paths(Query *root,
best_or_subclause_indices(root,
rel,
clausenode->clause->args,
clausenode->subclauseindices,
restrictinfo->clause->args,
restrictinfo->subclauseindices,
pathnode);
add_path(rel, (Path *) pathnode);