Hi Lars,
> psql (14.1, server 12.6 (Ubuntu 12.6-0ubuntu0.20.04.1))
Maybe you can upgrade to 12.9 ( from 12.6 ) ( https://www.postgresql.org/docs/release/12.9/ )
And the next minor release = pg 12.10 is expected on February 10th, 2022 https://www.postgresql.org/developer/roadmap/
select
schemaname
,relname
,n_tup_ins
,n_tup_upd
,n_tup_del
,n_tup_hot_upd
,n_live_tup
,n_dead_tup
from pg_stat_all_tables
where n_dead_tup > 0 and schemaname='pg_catalog'
;
>>
>> Here is a slow one:
>> https://explain.depesz.com/s/tUt5
>>
>> and here is fast one :
>> https://explain.depesz.com/s/yYG4
>
>The only difference is that this is sometimes many times slower.
>
> Finalize Aggregate (cost=42021.15..42021.16 rows=1 width=8) (actual time=50602.755..117201.768 rows=1 loops=1)
> -> Gather (cost=42020.94..42021.15 rows=2 width=8) (actual time=130.527..117201.754 rows=3 loops=1)
> Workers Planned: 2
> Workers Launched: 2
>
>> Here are my settings (the server has around 256 GB og memory) :
>
Hi
Here is some more info.
>What version of postgres ? What OS/version ?
psql (14.1, server 12.6 (Ubuntu 12.6-0ubuntu0.20.04.1))
>https://wiki.postgresql.org/wiki/Slow_Query_Questions
>
>Are there any server logs around that time ?
Yes but nothing in the logs that I could find.
>Or session logs for the slow query ?
>
>Is it because the table creation is locking (rows of) various system catalogs ?
>I'm not sure if it'd be a single, long delay that you could see easily with
>log_lock_waits, or a large number of small delays, maybe depending on whether
>your table creation is done within a transaction.
Added log_lock_waits but could not anything new in the logs
SHOW deadlock_timeout ;
deadlock_timeout
------------------
1s
SHOW log_lock_waits;
log_lock_waits
----------------
on
(1 row)
In the logs I only things like this
LOG: duration: 71841.233 ms statement: CREATE UNLOGGED TABLE IF NOT EXISTS tmp_klimagass.styredata_tidligbygg_159298.....
LOG: duration: 12645.127 ms statement: GRANT SELECT ON TABLE tmp_klimagass.vaerdata_159296 TO org_mojo2_sl_read_role;
LOG: duration: 15783.611 ms statement: EXPLAIN ANALYZE select count(*)
from information_schema.tables;
LOG: duration: 35594.903 ms statement: EXPLAIN ANALYZE select count(*)
Can not find anything here either
select relation::regclass, * from pg_locks where not granted;
relation | locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid | virtualtransaction | pid | mode | granted | fastpath
----------+----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+-----+------+---------+----------
(0 rows)
Time: 55.270 ms
>
>--
>Justin
Thanks
Lars
