On Tue, Aug 14, 2018 at 3:52 PM, Marko Tiikkaja <marko@joh.to> wrote: > On Tue, Aug 14, 2018 at 7:10 AM, Amit Kapila <amit.kapila16@gmail.com> > wrote: >> >> Yeah, one idea could be that we detect this in >> max_parallel_hazard_walker during the very first pass it performs on >> query-tree. Basically, in the SubLink node check, we can detect >> whether the subselect has Limit/Offset clause and if so, then we can >> treat it as parallel_unsafe. I have tried that way and it prohibits >> the parallel plan for the reported queries. However, I think more >> analysis and verification is required to see if it can happen in any >> other related cases. > > > This seems broken as well: > > create table qwr(a int not null, b int not null, c text not null); > insert into qwr select i, i, (select prosrc from pg_proc where > oid=11734) from generate_series(1, 128000) i; > set parallel_setup_cost to 0; > analyze qwr; > select count(*) from qwr where (a, b) in (select a, row_number() over() > from qwr); >
I am getting below error in above steps:
postgres=# insert into qwr select i, i, (select prosrc from pg_proc where oid=11734) from generate_series(1, 128000) i; ERROR: null value in column "c" violates not-null constraint DETAIL: Failing row contains (1, 1, null).
Sorry, try this instead:
insert into qwr select i, i, (select prosrc from pg_proc where oid='ts_debug(regconfig,text)'::regprocedure) from generate_series(1, 128000) i;
