| From: | Maciek Sakrejda <m(dot)sakrejda(at)gmail(dot)com> |
|---|---|
| To: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
| Cc: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Anibal David Acosta <aa(at)devshock(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: how to avoid deadlock on masive update with multiples delete |
| Date: | 2012-10-05 15:08:19 |
| Message-ID: | CAOtHd0A0UNJYTeVDsn6uY2d-6f2+=s5EkQFwNV0ASa4PqAk8yw@mail.gmail.com |
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| Lists: | pgsql-performance |
Presumably something like this?:
maciek=# CREATE TABLE test AS SELECT g, random() FROM
generate_series(1,1000) g;
CREATE
maciek=# EXPLAIN DELETE FROM test USING (SELECT g FROM test ORDER BY
ctid) x where x.g = test.g;
QUERY PLAN
---------------------------------------------------------------------------------
Delete on test (cost=188.99..242.34 rows=1940 width=34)
-> Hash Join (cost=188.99..242.34 rows=1940 width=34)
Hash Cond: (x.g = public.test.g)
-> Subquery Scan on x (cost=135.34..159.59 rows=1940 width=32)
-> Sort (cost=135.34..140.19 rows=1940 width=10)
Sort Key: public.test.ctid
-> Seq Scan on test (cost=0.00..29.40 rows=1940 width=10)
-> Hash (cost=29.40..29.40 rows=1940 width=10)
-> Seq Scan on test (cost=0.00..29.40 rows=1940 width=10)
(9 rows)
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