On 09/17/2011 06:43 PM, Kai Krueger wrote:
* start with low default work_mem and maintenance_work_mem settings
and raise them on a per statement level, so making the appropriate
buffer for a given operation (work_mem for ORDER BY,
maintenance_work_mem for CREATE INDEX) as large as possible and
then shrinking it back to its default size afterwards
Is it possible to adjust work_mem and maintanance_work_mem at run time?
yes, see e.g.:
http://www.depesz.com/index.php/2011/07/03/understanding-postgresql-conf-work_mem/
[...]
What has to be noted though, is that you can change work_mem using
normal sql query – and it will be changed for this particular session
only.
So, it might make sense to set work_mem in postgresql.conf to
relatively low value (1-10MB), and then, find out which queries would
use more, and change the application to issue
set work_mem = '100MB'
before running them, and
reset work_mem
afterwards.
[...]
--
hartmut
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