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

   From: Remigiusz Sokolowski <rems@gdansk.sprint.pl>
   cc: pgsql-general@postgreSQL.org, pgsql-hackers@postgreSQL.org
   Content-Type: TEXT/PLAIN; charset=US-ASCII
   Sender: owner-pgsql-general@postgreSQL.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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Karl DeBisschop <kdebisschop@spaceheater.infoplease.com>
617.832.0332 (Fax: 617.956.2696)

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