From: | Bruce Momjian <bruce(at)momjian(dot)us> |
---|---|
To: | PostgreSQL-development <pgsql-hackers(at)postgreSQL(dot)org> |
Subject: | Avoiding repeated ON COMMIT truncation for temporary tables |
Date: | 2011-03-12 01:07:53 |
Message-ID: | 201103120107.p2C17rd22697@momjian.us |
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Lists: | pgsql-hackers |
Currently, if you create a temporary table with the ON COMMIT action of
DELETE ROWS, the table will truncated for every commit, whether there is
any data in the table or not.
I measured the overhead using this test:
$ (echo 'CREATE TEMPORARY TABLE TEST2 (x int);'; jot -b 'SELECT 1;'
10000) | time psql test > /dev/null
6.93 real 0.93 user 0.78 sys
$ (echo 'CREATE TEMPORARY TABLE TEST2 (x int) ON COMMIT DELETE ROWS;';
jot -b 'SELECT 1;' 10000) | time psql test > /dev/null
7.93 real 1.02 user 0.72 sys
The overhead measures 14%. Is there a simple way to avoid the repeated
truncation overhead of such cases? Is this a TODO?
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
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