André Volpato escreveu:
David Wilson escreveu:
On Wed, Aug 20, 2008 at 2:30 PM, André Volpato
<andre.volpato@xxxxxxxxxxxxxxxxxxxxx> wrote:
The CPU is 100% used since a few hours ago. Can anyone tell why?
Sounds like you've just got a CPU bound query. The data may even all
be in cache.
Some information on database size, along with EXPLAIN results for your
queries, would help here.
The query itself runs smoothly, almost with no delay.
You where right about the cache.
After some experiences, I noticed that the arrays are being used, but
only for a short time...
So, what is slowing down is the CPU (Intel(R) Pentium(R) Dual CPU
E2160 @ 1.80GHz)
In practice, I have noticed that dual 1.8 is worse than single 3.0. We
have another server wich
is a Pentium D 3.0 GHz, that runs faster.
Explain output:
HashAggregate (cost=19826.23..19826.96 rows=73 width=160) (actual
time=11826.754..11826.754 rows=0 loops=1)
-> Subquery Scan b2 (cost=19167.71..19817.21 rows=722 width=160)
(actual time=11826.752..11826.752 rows=0 loops=1)
Filter: (bds_internacoes(200805, 200806, (b2.cod)::text,
'qtdI'::text, 'P'::bpchar) >= 1::numeric)
-> Limit (cost=19167.71..19248.89 rows=2165 width=48) (actual
time=415.157..621.043 rows=28923 loops=1)
-> HashAggregate (cost=19167.71..19248.89 rows=2165
width=48) (actual time=415.155..593.309 rows=28923 loops=1)
-> Bitmap Heap Scan on bds_beneficiario b
(cost=832.53..18031.61 rows=56805 width=48) (actual time=68.259..160.912
rows=56646 loops=1)
Recheck Cond: ((benef_referencia >= 200805)
AND (benef_referencia <= 200806))
-> Bitmap Index Scan on ibds_beneficiario2
(cost=0.00..818.33 rows=56805 width=0) (actual time=63.293..63.293
rows=56646 loops=1)
Index Cond: ((benef_referencia >=
200805) AND (benef_referencia <= 200806))
Total runtime: 11827.374 ms
Postgres read the array in less than 1 sec, and the other 10s he takes
100% of CPU usage,
wich is, in this case, one of the two cores at 1.8GHz.
I am a bit confused about what CPU is best for Postgres. Our apps is
mostly read, with
a few connections and heavy queryes.
Does it worth a multi-core ?
--
[]´s, ACV
