On Thu, 23 Aug 2007 21:16:48 +0400, Joshua D. Drake <jd@xxxxxxxxxxxxxxxxx>
wrote:
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Max Zorloff wrote:
Hello.
I have a subject setup and a few questions.
The first one is this. PHP establishes a connection to the Postgres
database through pg_pconnect().
Don't use pconnect. Use pgbouncer or pgpool.
Then it
runs some query, then the script returns, leaving the persistent
connection hanging. But the trouble
is that in this case any query takes significantly more time to execute
than in the case of one PHP script
running the same query with different parameters for N times. How can I
achieve the same performance in the first
case? Persistent connections help but not enough - the queries are still
10 times slower than they would be on
the 2nd time.
Well you haven't given us any indication of data set or what you are
trying to do. However, I can tell you, don't use pconnect, its broke ;)
The data set is some 400mb database with ~100 SELECT queries running in a
second
and some 7-10 pl/pgsql functions doing select checks and then 2-3
insert/updates.
The second one is that the machine with this setup is dual core Xeon
2.8ghz. I've read somewhere about
the switching context problem and bad postgres performance. What are the
effects? What are the symptoms?
You likely do not have this problem if you are running anywhere near a
current PostgreSQL release but you can check it with vmstat.
I have 8.0.13 postgres. How do I check the thing with vmstat?
And what will be the performance gain if I change the machine to equal
Athlon?
Depends on the work load.
Right now 100 concurrent users completely use the cpu. So I'm trying to
find out where the problem lies.
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