Re: [GENERAL] Slow query plan used
| От | Andreas Kretschmer |
|---|---|
| Тема | Re: [GENERAL] Slow query plan used |
| Дата | |
| Msg-id | 64d2c8f8-1bf1-21f1-563f-e2b0d414fcfe@a-kretschmer.de обсуждение исходный текст |
| Ответ на | [GENERAL] Slow query plan used ("Wetzel, Juergen (Juergen)" <wetzel@avaya.com>) |
| Ответы |
Re: [GENERAL] Slow query plan used
|
| Список | pgsql-general |
Am 30.05.2017 um 10:42 schrieb Wetzel, Juergen (Juergen):
> I have a question concerning the query planner. I observe that chosen query plan differs on length and content of a like
> search expression. We have a view combining data from two tables, both containing same number of rows (round about 30000).
> Used PostgreSQL version is 9.3.15 on Windows. DDL of tables and view see below.
> I have a question concerning the query planner. I observe that chosen query plan differs on length and content of a like
> search expression. We have a view combining data from two tables, both containing same number of rows (round about 30000).
> Used PostgreSQL version is 9.3.15 on Windows. DDL of tables and view see below.
the query is on DOCUMENTDATA, but plan and DDL for c3k_documentdata and other tables.
> Only 130 rows out of the 30000 have ARCHIVED = 0
in this case i would suggest a partial index:
create index <indexname> on <tablename> (archived) where archived = 0;
You can also increase the statistics for the columns subject and mailContent
ALTER TABLE <tablename> ALTER COLUMN <column_name> SET STATISTICS = 1000;
(as example, the default-value is 100)
(as example, the default-value is 100)
Regards, Andreas
-- 2ndQuadrant - The PostgreSQL Support Company. www.2ndQuadrant.com
В списке pgsql-general по дате отправления: