Re: startup process stuck in recovery

> On Oct 10, 2017, at 08:05, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> You're right, I was testing on HEAD, so that patch might've obscured
> the problem. But the code looks like it could still be O(N^2) in
> some cases. Will look again later.

I was able to reproduce this on 9.5.9 with the following:

DO $$
DECLARE
i int := 1;
BEGIN
FOR i IN 1..12000 LOOP
BEGIN
PERFORM f();
i := i / 0;
EXCEPTION
WHEN division_by_zero THEN
END;
END LOOP;
END;
$$ language plpgsql;

where f() is:

CREATE OR REPLACE FUNCTION f() RETURNS VOID AS $$
BEGIN
CREATE TEMPORARY TABLE test_table ON COMMIT DROP AS SELECT i FROM generate_series(1, 100) i;
END:
$$ language plpgsql;

A couple of observations:

-- In this version, I couldn't do a select * from pg_locks() on the secondary without getting an out-of-shared-memory error.
-- If I increased max_locks_per_transaction to 15000, the problem didn't occur, even if I bumped up the number of iterations in the first to 20000.

--
-- Christophe Pettus
xof(at)thebuild(dot)com