Re: simple update queries take a long time - postgres 8.3.1

[mark <markkicks@xxxxxxxxx>]

On Tue, Apr 1, 2008 at 12:44 AM, mark <markkicks@xxxxxxxxx> wrote:

On Mon, Mar 31, 2008 at 11:18 PM, Tomasz Ostrowski <tometzky@xxxxxxxxxxxxx> wrote:

On 2008-03-31 21:16, mark wrote:

> is the query I am running , and it takes over 10 seconds to complete
> this query...
> update users set number_recieved=number_recieved+1 where
> uid=738889333;

Every time or only sometimes?

i checked again, and it seems to be only sometimes..   and during these times there are lot of other queries too running which I can see from pg_stat_activity;

Upgrade to 8.3 will help as checkpoint writing algorithms were optimized
there for lots of RAM.

I already am running 8.3.1 [ i mentioned in subject]. I am having the default settings for those. can you pl. share the settings for check points:

current settings all default
#checkpoint_segments = 3                # in logfile segments, min 1, 16MB each
#checkpoint_timeout = 5min              # range 30s-1h
#checkpoint_completion_target = 0.5     # checkpoint target duration, 0.0 - 1.0
#checkpoint_warning = 30s               # 0 is off

this is what I have on pg_stat_bgwriter ; how much should I increase checkpoint_segment & checkpoint_completion_target to? thanks a lot!

postgres=# select * from pg_stat_bgwriter;
 checkpoints_timed | checkpoints_req | buffers_checkpoint | buffers_clean | maxwritten_clean | buffers_backend | buffers_alloc
-------------------+-----------------+--------------------+---------------+------------------+-----------------+---------------
                42 |            1051 |            8035125 |         21954 |               42 |          241519 |      10394696