updates (postgreSQL) very slow
От | Bobbie van der Westhuizen |
---|---|
Тема | updates (postgreSQL) very slow |
Дата | |
Msg-id | 404EDEE7.18636.192BB481@localhost обсуждение исходный текст |
Ответы |
Re: updates (postgreSQL) very slow
Re: updates (postgreSQL) very slow |
Список | pgsql-general |
Hi, Can someone please help me. My PostgreSQL queries are very slow, especially update statements. What can I do to improve the speed? I have already try VACUUM and ANALYZE. " From the command line I have vacuumdb -z -a -f from inside psql: database=# VACUUM FULL ANALYZE;" I work on a Linux (Mandake 9.1) computer with 2 Zeon Prosessors and 4Gig of ram. The HD on which postgreSQL is running is a 80Gig drive and read 55Mbit/Sec. The next query is an example. The table in which I work here contains 747 524 records and 14 fields (columns). bons_acc=# explain update edc_ww set edc=null; QUERY PLAN ------------------------------------- --------------------------- Seq Scan on edc_ww (cost=0.00..156793.91 rows=3491 width=184) (1 row) Time: 0.61 ms bons_acc=# update edc_ww set edc=null; UPDATE 747524 Time: 7628686.23 ms This is just a Seq Scan where a numeric field must be updated to NULL but if I run it you can see that this simple query takes forever (7628686.23 ms this is over 2 hours for only updating 747524 records!). I dont think that the tables are to big? Could it be my hardware/software/postgreSQL? What can I do to optimise postgreSQL? I already increased the shared buffer in the conf. file aswell. Bobbie______________________________________________ ____________ Bobbie van der Westhuizen Quantitative Animal Breeding (BLUP) ARC - Animal Improvement Institute +27-12-672-9128 (o/h) +27-12-665-1419 (fax) bobbie@irene.agric.za ____________________________________________________ ______
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