Fix ndistinct estimates with system attributes
When estimating the number of groups using extended statistics, the code was discarding information about system attributes. This led to strange situation that SELECT 1 FROM t GROUP BY ctid; could have produced higher estimate (equal to pg_class.reltuples) than SELECT 1 FROM t GROUP BY a, b, ctid; with extended statistics on (a,b). Fixed by retaining information about the system attribute. Backpatch all the way to 10, where extended statistics were introduced. Author: Tomas Vondra Backpatch-through: 10
This commit is contained in:
parent
83ba02c83e
commit
2a307df1bb
|
@ -4025,11 +4025,11 @@ estimate_multivariate_ndistinct(PlannerInfo *root, RelOptInfo *rel,
|
||||||
|
|
||||||
attnum = ((Var *) varinfo->var)->varattno;
|
attnum = ((Var *) varinfo->var)->varattno;
|
||||||
|
|
||||||
if (!AttrNumberIsForUserDefinedAttr(attnum))
|
if (AttrNumberIsForUserDefinedAttr(attnum) &&
|
||||||
|
bms_is_member(attnum, matched))
|
||||||
continue;
|
continue;
|
||||||
|
|
||||||
if (!bms_is_member(attnum, matched))
|
newlist = lappend(newlist, varinfo);
|
||||||
newlist = lappend(newlist, varinfo);
|
|
||||||
}
|
}
|
||||||
|
|
||||||
*varinfos = newlist;
|
*varinfos = newlist;
|
||||||
|
|
Loading…
Reference in New Issue