From: | Hans-Jürgen Schönig <hs(at)cybertec(dot)at> |
---|---|
To: | pgsql-sql(at)postgresql(dot)org |
Subject: | Bad performing DELETE |
Date: | 2000-11-27 11:39:32 |
Message-ID: | 3A2247F4.85C70143@cybertec.at |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-sql |
>
I have two tables: t_haus is about 1400 row and t_host has 364000 entries.
Both tables are indexed on edvnr. I did a vacuum on my db and all indices
are rebuild.
I want to delete all Entries in t_haus where a row can be found in t_host.
When using "delete from t_haus where t_haus.edvnr=t_host.edvnr; " the
database performs extremely bad.
explain delete from t_haus where t_haus.edvnr=t_host.edvnr;
NOTICE: QUERY PLAN:
Merge Join (cost=52178.53..56754.63 rows=6299767 width=14)
-> Sort (cost=52038.25..52038.25 rows=364359 width=4)
-> Seq Scan on t_host (cost=0.00..11700.59 rows=364359 width=4)
-> Sort (cost=140.27..140.27 rows=1729 width=10)
-> Seq Scan on t_haus (cost=0.00..47.29 rows=1729 width=10)
EXPLAIN
What can I do to speed it up?
I've also had troubles with DELETE before (when doing joins in the
WHERE clause).
Hans
From | Date | Subject | |
---|---|---|---|
Next Message | Bruno Boettcher | 2000-11-27 11:44:23 | removing a DB?? |
Previous Message | Jens Hartwig | 2000-11-27 11:34:38 | Re: removing a DB?? |