Re: [GENERAL] Re: [HACKERS] postgres processes

From: Remigiusz Sokolowski <rems(at)gdansk(dot)sprint(dot)pl>
cc: pgsql-general(at)postgreSQL(dot)org, pgsql-hackers(at)postgreSQL(dot)org
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> The defaults in the Apache configuration are
>
> StartServers 5
> MaxClients 256
> MinSpareServers 5
> MaxSpareServers 10
>
> This means, that at startup Apache will create 5 server
> processes that can handle requests simultaneously. When the
> site gets busy and some of them take longer to handle
> requests (especially scripting requests), it will start new
> servers (max one per second) until the limit of 256 parallel
> server processes is reached. If they finish their requests
> and become idle again, some of them get killed if there are
> more than 10 idle Apache processes.
>
> This is normally a good policy. It ensures that small file
> requests can still get served while some long running CGI's
> block their server process.

My problem is, that server is used not only as database server, but also
(and in general) as mail server - I think that tehre are some other
services too.
I've used persistent connections to database (and I think I now understand
why so big processor usage), so postgres processes haven't die after
serve requests but wait for another.
Hmm... I have one question more - every postgres process takes about 5% of
processor time ( I've used to measure top command ) - it is normal or may
be processor is too slow?
Rem

We use a similar configuration, and initially had similar problems.
We just don't use persistent connections in php anymore, and things
work fine - In our case, the number of reconnects saved by pconnect
would be small anyway.

Another strategy would be to start a second apache server on a
different port or different machine, use it only for redirects to the
pages that call postgres (assuming this is not your whole site). Then
throttle the second server back as described above (we haven't
actually done this - but it seems it should work).

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