Em ter., 14 de set. de 2021 às 17:11, Tom Lane <tgl@sss.pgh.pa.us> escreveu:
Zhihong Yu <zyu@yugabyte.com> writes: > In the fix, isUsedSubplan is used to tell whether any given subplan is used. > Since only one subplan is used, I wonder if the array can be replaced by > specifying the subplan is used.
That doesn't seem particularly more convenient. The point of the bool array is to merge the results from examination of (possibly) many AlternativeSubPlans.
Impressive quick fix, but IMHO I also think it's a bit excessive.
I would like to ask if this alternative fix (attached) would also solve the problem or not. Apparently, it passes the proposed test and in regress.
postgres=# create temp table exists_tbl (c1 int, c2 int, c3 int) partition by list (c1); CREATE TABLE postgres=# create temp table exists_tbl_null partition of exists_tbl for values in (null); CREATE TABLE postgres=# create temp table exists_tbl_def partition of exists_tbl default; CREATE TABLE postgres=# insert into exists_tbl select x, x/2, x+1 from generate_series(0,10) x; INSERT 0 11 postgres=# analyze exists_tbl; ANALYZE postgres=# explain (costs off) postgres-# explain (costs off); ERROR: syntax error at or near "explain" LINE 2: explain (costs off); ^ postgres=# explain (costs off) postgres-# select * from exists_tbl t1 postgres-# where (exists(select 1 from exists_tbl t2 where t1.c1 = t2.c2) or c3 < 0); QUERY PLAN ------------------------------------------------------ Append -> Seq Scan on exists_tbl_null t1_1 Filter: ((SubPlan 1) OR (c3 < 0)) SubPlan 1 -> Append -> Seq Scan on exists_tbl_null t2_1 Filter: (t1_1.c1 = c2) -> Seq Scan on exists_tbl_def t2_2 Filter: (t1_1.c1 = c2) -> Seq Scan on exists_tbl_def t1_2 Filter: ((hashed SubPlan 2) OR (c3 < 0)) SubPlan 2 -> Append -> Seq Scan on exists_tbl_null t2_4 -> Seq Scan on exists_tbl_def t2_5 (15 rows)
