Search Postgresql Archives

Re: slow select in big table

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On Fri, Apr 3, 2009 at 2:18 AM, rafalak <rafalak@xxxxxxxxx> wrote:
Hello i have big table
80mln records, ~6GB data, 2columns (int, int)

if query
select count(col1) from tab where col2=1234;
return low records (1-10) time is good 30-40ms
but when records is >1000 time is >12s


How to increse performace ?


my postgresql.conf
shared_buffers = 810MB
temp_buffers = 128MB
work_mem = 512MB
maintenance_work_mem = 256MB
max_stack_depth = 7MB
effective_cache_size = 800MB


db 8.3.7
server, atlon dual-core 2,0Ghz, 2GB RAM, SATA


--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general
Is the table has indexes?
Decreasing the work_mem also increase performance.
Monitor these changes by explain the query plan.

Regards,
Abbas.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]
  Powered by Linux