Re: [sqlsmith] Parallel worker crash on seqscan

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: [sqlsmith] Parallel worker crash on seqscan
Дата
Msg-id 21817.1479746628@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Re: [sqlsmith] Parallel worker crash on seqscan  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: [sqlsmith] Parallel worker crash on seqscan  (Robert Haas <robertmhaas@gmail.com>)
Список pgsql-hackers
I wrote:
> Like Ashutosh, I can't reproduce the crash, so it's hard to speculate much
> further.

Ah-hah: now I can.  The recipe lacks these important steps:

set parallel_setup_cost TO 0;
set parallel_tuple_cost TO 0;

That changes the plan to
Limit  (cost=0.00..0.06 rows=1 width=64)  ->  Nested Loop  (cost=0.00..57.25 rows=1000 width=64)        ->  Function
Scanon pg_show_all_settings a  (cost=0.00..10.00 rows=1000 width=64)        ->  Limit  (cost=0.00..0.03 rows=1
width=32)             ->  Gather  (cost=0.00..3.54 rows=130 width=32)                    Workers Planned: 2
      ->  Parallel Seq Scan on pg_opclass  (cost=0.00..3.54 rows=54 width=32) 

so what we've got is a case where a parameter computed by the FunctionScan
(in the master) would need to be passed into the parallel workers at
runtime.  Do we have code for that at all?  If so where is it?
        regards, tom lane



В списке pgsql-hackers по дате отправления:

Предыдущее
От: "Daniel Verite"
Дата:
Сообщение: Re: Improvements in psql hooks for variables
Следующее
От: Robert Haas
Дата:
Сообщение: Re: [sqlsmith] Parallel worker crash on seqscan