(Resending with -hackers) It seems like your patch should also check "inh" in examine_variable and statext_expressions_load.
Which leads to another issue in stable branches: ANALYZE builds only non-inherited stats, but they're incorrectly used for inherited queries - the rowcount estimate is worse on inheritence parents with extended stats than without. CREATE TABLE p(i int, j int); CREATE TABLE p1() INHERITS(p); INSERT INTO p SELECT a, a/10 FROM generate_series(1,9)a; INSERT INTO p1 SELECT a, a FROM generate_series(1,999)a; CREATE STATISTICS ps ON i,j FROM p; VACUUM ANALYZE p,p1; postgres=# explain analyze SELECT * FROM p GROUP BY 1,2; HashAggregate (cost=26.16..26.25 rows=9 width=8) (actual time=2.571..3.282 rows=1008 loops=1) postgres=# begin; DROP STATISTICS ps; explain analyze SELECT * FROM p GROUP BY 1,2; rollback; HashAggregate (cost=26.16..36.16 rows=1000 width=8) (actual time=2.167..2.872 rows=1008 loops=1) I guess examine_variable() should have corresponding logic to the hardcoded !inh in analyze.c. -- Justin
