database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-08 00:47:37 +03:00
Code Activity

Simplify the planner's new representation of indexable clauses a little.

Browse Source 
In commit 1a8d5afb0, I thought it'd be a good idea to define
IndexClause.indexquals as NIL in the most common case where the given
clause (IndexClause.rinfo) is usable exactly as-is.  It'd be more
consistent to define the indexquals in that case as being a one-element
list containing IndexClause.rinfo, but I thought saving the palloc
overhead for making such a list would be worthwhile.

In hindsight, that was a great example of "premature optimization is the
root of all evil": it's complicated everyplace that needs to deal with
the indexquals, requiring duplicative code to handle both the simple
case and the not-simple case.  I'd initially found that tolerable but
it's getting less so as I mop up some areas that I'd not touched in
1a8d5afb0.  In any case, two more pallocs during a planner run are
surely at the noise level (a conclusion confirmed by a bit of
microbenchmarking).  So let's change this decision before it becomes
set in stone, and insist that IndexClause.indexquals always be a valid
list of the actual index quals for the clause.

Discussion: https://postgr.es/m/24586.1550106354@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2019-02-14 19:37:30 -05:00
parent 86eea78694
commit 8fd3fdd85a
4 changed files with 63 additions and 117 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
src/backend/optimizer/path/indxpath.c
View File

@@ -2435,7 +2435,7 @@ match_clause_to_indexcol(PlannerInfo *root,
{
iclause = makeNode(IndexClause);
iclause->rinfo = rinfo;
iclause->indexquals = NIL;
iclause->indexquals = list_make1(rinfo);
iclause->lossy = false;
iclause->indexcol = indexcol;
iclause->indexcols = NIL;
@@ -2599,7 +2599,7 @@ match_opclause_to_indexcol(PlannerInfo *root,
{
iclause = makeNode(IndexClause);
iclause->rinfo = rinfo;
iclause->indexquals = NIL;
iclause->indexquals = list_make1(rinfo);
iclause->lossy = false;
iclause->indexcol = indexcol;
iclause->indexcols = NIL;
@@ -2819,7 +2819,7 @@ match_saopclause_to_indexcol(RestrictInfo *rinfo,
IndexClause *iclause = makeNode(IndexClause);
iclause->rinfo = rinfo;
iclause->indexquals = NIL;
iclause->indexquals = list_make1(rinfo);
iclause->lossy = false;
iclause->indexcol = indexcol;
iclause->indexcols = NIL;
@@ -3078,7 +3078,7 @@ expand_indexqual_rowcompare(RestrictInfo *rinfo,
* usable as index quals.
*/
if (var_on_left && !iclause->lossy)
iclause->indexquals = NIL;
iclause->indexquals = list_make1(rinfo);
else
{
/*