On 3/8/17 14:22, Pavel Stehule wrote: > 1. will be background session process closed automatically when parent > process is closed?
If the communications queue goes away the process will eventually die. This is similar to how a backend process will eventually die if the client goes away. Some more testing would be good here.
what means "eventually die"?
I called pg_sleep() in called subprocess.
Cancel, terminating parent process has not any effect. It is maybe artificial test.
Little bit more realistic - waiting on table lock in background worker was successful - and when parent was cancelled, then worker process was destroyed too.
But when parent was terminated, then background worker process continued.
What is worse - the background worker had 100% CPU and I had to restart notebook.
CREATE OR REPLACE FUNCTION public.foo()RETURNS voidLANGUAGE plpythonu
AS $function$
with plpy.BackgroundSession() as a: a.execute('update foo2 set a = 30') a.execute('insert into foo2 values(10)')
$function$
postgres=#
I blocked foo2 in another session.
Regards
Pavel
> 2. what timeouts are valid for this process - statement timeout, idle in > transaction timeout
Those should work the same way. It's the same code that runs the queries, starts/stops transactions, etc. > I see significant risk on leaking sessions.
Yeah, that's a valid concern. But I think it works ok. > There can be more doc and examples in plpython doc. It will be main > interface for this feature. Mainly about session processing.
OK, I'll look into that again.
-- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
