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* Blocking queries on a hot standby?
@ 2023-09-15 04:30 Victor Sudakov <vas@sibptus.ru>
0 siblings, 2 replies; 3+ messages in thread
From: Victor Sudakov @ 2023-09-15 04:30 UTC (permalink / raw)
To: pgsql-admin@lists.postgresql.org
Dear Colleagues,
Can you imagine, at least theoretically, any kind of query on a
physical replica (hot standby) which would block other queries on the
same replica?
--
Victor Sudakov VAS4-RIPE
http://vas.tomsk.ru/
2:5005/49@fidonet
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Blocking queries on a hot standby?
@ 2023-09-15 06:24 Laurenz Albe <laurenz.albe@cybertec.at>
parent: Victor Sudakov <vas@sibptus.ru>
1 sibling, 0 replies; 3+ messages in thread
From: Laurenz Albe @ 2023-09-15 06:24 UTC (permalink / raw)
To: Victor Sudakov <vas@sibptus.ru>; pgsql-admin@lists.postgresql.org
On Fri, 2023-09-15 at 04:30 +0000, Victor Sudakov wrote:
> Can you imagine, at least theoretically, any kind of query on a
> physical replica (hot standby) which would block other queries on the
> same replica?
I cannot.
Yours,
Laurenz Albe
^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: Blocking queries on a hot standby?
@ 2023-09-18 03:41 Rui DeSousa <rui@crazybean.net>
parent: Victor Sudakov <vas@sibptus.ru>
1 sibling, 0 replies; 3+ messages in thread
From: Rui DeSousa @ 2023-09-18 03:41 UTC (permalink / raw)
To: Victor Sudakov <vas@sibptus.ru>; +Cc: Pgsql-admin <pgsql-admin@lists.postgresql.org>
> On Sep 15, 2023, at 12:30 AM, Victor Sudakov <vas@sibptus.ru> wrote:
>
> Can you imagine, at least theoretically, any kind of query on a
> physical replica (hot standby) which would block other queries on the
> same replica?
The only thing that comes to mine is advisory locks and also queries can block replication replay.
prod=# select pg_is_in_recovery();
-[ RECORD 1 ]-----+--
pg_is_in_recovery | t
prod=# select * from blocked_session;
-[ RECORD 1 ]---+-----------------------------
pid | 39330
tree | 39330
root | 39330
level | 0
user | rui
state | idle
state_duration | 00:01:01.663597
wait_event_type | Client
wait_event | ClientRead
lockmode | ExclusiveLock
locktype | advisory
granted | t
lock_wait |
blocked | 1
query | select pg_advisory_lock(42);
objects |
-[ RECORD 2 ]---+-----------------------------
pid | 39327
tree | 39330.39327
root | 39330
level | 1
user | rui
state | active
state_duration | 00:00:51.407894
wait_event_type | Lock
wait_event | advisory
lockmode | ExclusiveLock
locktype | advisory
granted | f
lock_wait | 00:00:51.407746
blocked | 0
query | select pg_advisory_lock(42);
objects |
^ permalink raw reply [nested|flat] 3+ messages in thread
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2023-09-15 04:30 Blocking queries on a hot standby? Victor Sudakov <vas@sibptus.ru>
2023-09-15 06:24 ` Laurenz Albe <laurenz.albe@cybertec.at>
2023-09-18 03:41 ` Rui DeSousa <rui@crazybean.net>
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