Re: update functions locking tables - Mailing list pgsql-general
| From | Clodoaldo Pinto |
|---|---|
| Subject | Re: update functions locking tables |
| Date | |
| Msg-id | a595de7a05083004133fb5ba99@mail.gmail.com Whole thread Raw |
| In response to | Re: update functions locking tables (Michael Fuhr <mike@fuhr.org>) |
| Responses |
Re: update functions locking tables
("Jim C. Nasby" <jnasby@pervasive.com>)
|
| List | pgsql-general |
2005/8/29, Michael Fuhr <mike@fuhr.org>:
>
> In general, writers shouldn't block readers. Have you examined
> pg_locks? Do you know exactly what the blocked queries are, or can
> you find out from pg_stat_activity (stats_command_string must be
> enabled)? Are you doing any explicit locking (LOCK statement)?
>
This is one of the blocked queries:
select count (*) from times_producao where pontos_0 - pontos_7 > 0;
These selects were done during the updating:
select * from pg_locks;
relation | database | transaction | pid | mode | granted
----------+----------+-------------+-------+---------------------+---------
1813938 | 1813868 | | 7040 | AccessShareLock | t
1813938 | 1813868 | | 7040 | RowExclusiveLock | t
1813938 | 1813868 | | 7040 | ShareLock | t
1813938 | 1813868 | | 7040 | AccessExclusiveLock | t
1813939 | 1813868 | | 7040 | AccessShareLock | t
1813939 | 1813868 | | 7040 | RowExclusiveLock | t
1813939 | 1813868 | | 7040 | ShareLock | t
1813939 | 1813868 | | 7040 | AccessExclusiveLock | t
1813914 | 1813868 | | 24012 | AccessShareLock | f
1813892 | 1813868 | | 7040 | AccessShareLock | t
1813892 | 1813868 | | 7040 | RowExclusiveLock | t
1813914 | 1813868 | | 7040 | AccessShareLock | t
1813914 | 1813868 | | 7040 | RowExclusiveLock | t
1813914 | 1813868 | | 7040 | ShareLock | t
1813914 | 1813868 | | 7040 | AccessExclusiveLock | t
1813896 | 1813868 | | 7040 | AccessShareLock | t
16839 | 1813868 | | 12751 | AccessShareLock | t
2314110 | 1813868 | | 26871 | AccessShareLock | f
1813914 | 1813868 | | 26844 | AccessShareLock | f
| | 288553 | 26844 | ExclusiveLock | t
| | 288561 | 24012 | ExclusiveLock | t
| | 288548 | 7040 | ExclusiveLock | t
| | 288558 | 26871 | ExclusiveLock | t
1813914 | 1813868 | | 31212 | AccessShareLock | f
2314110 | 1813868 | | 7040 | AccessShareLock | t
2314110 | 1813868 | | 7040 | RowExclusiveLock | t
2314110 | 1813868 | | 7040 | ShareLock | t
2314110 | 1813868 | | 7040 | AccessExclusiveLock | t
| | 288556 | 31212 | ExclusiveLock | t
| | 288562 | 12751 | ExclusiveLock | t
1813887 | 1813868 | | 7040 | AccessShareLock | t
2314112 | 1813868 | | 7040 | ShareLock | t
2314112 | 1813868 | | 7040 | AccessExclusiveLock | t
1813907 | 1813868 | | 7040 | AccessShareLock | t
1813911 | 1813868 | | 7040 | AccessShareLock | t
(35 rows)
select *
from pg_stat_user_tables as a
inner join pg_locks as b
on a.relid = b.relation
;
relid | schemaname | relname | seq_scan | seq_tup_read |
idx_scan | idx_tup_fetch | n_tup_ins | n_tup_upd | n_tup_del |
relation | database | transaction | pid | mode |
granted
---------+------------+-------------------+----------+--------------+----------+---------------+-----------+-----------+-----------+----------+----------+-------------+-------+---------------------+---------
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 24012 | AccessShareLock | f
1813892 | public | last_date | 0 | 0 |
| | 0 | 0 | 0 | 1813892
| 1813868 | | 7040 | AccessShareLock | t
1813892 | public | last_date | 0 | 0 |
| | 0 | 0 | 0 | 1813892
| 1813868 | | 7040 | RowExclusiveLock | t
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 7040 | AccessShareLock | t
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 7040 | RowExclusiveLock | t
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 7040 | ShareLock | t
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 7040 | AccessExclusiveLock | t
1813896 | public | times | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813896
| 1813868 | | 7040 | AccessShareLock | t
2314110 | public | times_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 2314110
| 1813868 | | 31383 | AccessShareLock | f
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 12351 | AccessShareLock | f
2314110 | public | times_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 2314110
| 1813868 | | 26871 | AccessShareLock | f
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 26844 | AccessShareLock | f
2314110 | public | times_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 2314110
| 1813868 | | 24021 | AccessShareLock | f
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 31212 | AccessShareLock | f
2314110 | public | times_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 2314110
| 1813868 | | 7040 | AccessShareLock | t
2314110 | public | times_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 2314110
| 1813868 | | 7040 | RowExclusiveLock | t
2314110 | public | times_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 2314110
| 1813868 | | 7040 | ShareLock | t
2314110 | public | times_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 2314110
| 1813868 | | 7040 | AccessExclusiveLock | t
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 26872 | AccessShareLock | f
1813887 | public | datas | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813887
| 1813868 | | 7040 | AccessShareLock | t
1813914 | public | usuarios_producao | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813914
| 1813868 | | 8875 | AccessShareLock | f
1813907 | public | usuarios | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813907
| 1813868 | | 7040 | AccessShareLock | t
1813911 | public | usuarios_indice | 0 | 0 |
0 | 0 | 0 | 0 | 0 | 1813911
| 1813868 | | 7040 | AccessShareLock | t
(23 rows)
I had just enabled stats_command_string and in about 15 hours i will
be able to post pg_stat_activity.
Regards, Clodoaldo Pinto
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