From: | "Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com> |
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To: | "Bruce Momjian" <pgman(at)candle(dot)pha(dot)pa(dot)us> |
Cc: | "PostgreSQL-development" <pgsql-hackers(at)postgreSQL(dot)org> |
Subject: | Re: Timing of 'SELECT 1' |
Date: | 2004-03-10 15:00:55 |
Message-ID: | 6EE64EF3AB31D5448D0007DD34EEB34101AD85@Herge.rcsinc.local |
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Lists: | pgsql-hackers |
Bruce Momjian wrote:
> I am timing small queries, and found that a PREPARE/EXECUTE of "SELECT
> 1" takes about 1.2ms on my machine. A normal SELECT doesn't take much
> longer, so I am wondering why a simpler query isn't faster.
>
> Looking at log_executor_stats, I see the following. Execute shows
> nothing taking much time, mostly < .2ms, but the total seems high. I
> wonder if one of our standard query start/stop functions is taking too
> long and can be optimized.
There seems to be a 'PostgreSQL ping' time of about 1-2 ms in best case
conditions which limits the amount of queries you can fire off in 1
second, no matter how simple. In certain rare cases this is something
of a bottleneck. In my personal case it would be nice to see that time
lower because converted COBOL applications tend to generate a lot of
'simple' queries.
Merlin
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