On 03/29/2013 15:20, Franck Routier wrote:
Hi,
Hello,
I have a postgresql database (8.4) running in production whose
performance is degrading.
There is no single query that underperforms, all queries do.
Another interesting point is that a generic performance test
(https://launchpad.net/tpc-b) gives mediocre peformance when run on
the database, BUT the same test on a newly created database, on the
same pg cluster, on the same tablespace, does perform good.
So the problem seems to be limited to this database, even on newly
created tables...
What should I check to find the culprit of this degrading performance ?
Difficult to answer with so few details, but I would start by logging
slow queries, and run an explain analyze on them (or use auto_explain).
Check if you're CPU bound or I/O bound (top, iostats, vmstat, systat,
gstat..), check your configuration (shared_buffers,
effective_cache_size, work_mem, checkpoint_segments, cpu_tuple_cost, ...)
Franck
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