Re: simple update queries take a long time - postgres 8.3.1 - Mailing list pgsql-general

From mark
Subject Re: simple update queries take a long time - postgres 8.3.1
Date
Msg-id 82fa9e310804040843r57c80faclf7b6285a2f2a17e5@mail.gmail.com
Whole thread Raw
In response to Re: simple update queries take a long time - postgres 8.3.1  (Greg Smith <gsmith@gregsmith.com>)
Responses Re: simple update queries take a long time - postgres 8.3.1  (Tomasz Ostrowski <tometzky@batory.org.pl>)
List pgsql-general
On Thu, Apr 3, 2008 at 10:02 PM, Greg Smith <gsmith@gregsmith.com> wrote:
On Wed, 2 Apr 2008, mark wrote:
with no clients connected to the database when I try to shutdown the database [to apply new settings], it says database cant be shutdown.. for a long time both in smart and normal mode... then i had to go to immediate mode to shut down.. but then when i start it again.. it goes into recovery mode and runs for a while..is this the long recover time you are talking about?

If you couldn't shutdown using fast, that's something that deserves some investigation. That shouldn't happen unless there's a bad situation.
 
that is what I intended to write. I tried both smart and fast mode. and it says 'database wont shutdown', and immediate is the only mode that shutsdown the database.
 -> is shutting down in immediate mode a safe thing to do?
 -> how do i investigate why fast mode doesnt work?

stats with new settings are below..
  -> but even with this sometimes update queries take more than coupla seconds sometimes... 
  -> now i have a few '<IDLE> in transaction' statements which I did not have before.. is this OK?
  -> sometimes INSERT statements are also slow. is there any settings I can tweak to make INSERT statements fast?

bgwriter_lru_maxpages = 200             # 0-1000 max buffers written/round
checkpoint_segments = 96                # in logfile segments, min 1, 16MB each
checkpoint_timeout = 20min              # range 30s-1h
checkpoint_completion_target = 0.8      # checkpoint target duration, 0.0 - 1.0

postgres=# select * from pg_stat_bgwriter;
 checkpoints_timed | checkpoints_req | buffers_checkpoint | buffers_clean | maxwritten_clean | buffers_backend | buffers_alloc
-------------------+-----------------+--------------------+---------------+------------------+-----------------+---------------
                67 |               0 |            4012010 |        330679 |              570 |          184569 |       5379667
(1 row)



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