Frans wrote:
> I'm using Fedora Core 2, apache 2.0 and postgresql 7.4.6.
> Recently, the application is slowing down.
You don't say what the application is.
> When I check the process
> using "top", sometimes postmaster process time is increasing and the
> process is never end,
The postmaster is supposed to run all the time - this is called a
"daemon" in Unix terms. It is responsible for receiving new connections
and handling them. Backends handling queries will look something like:
postgres: richardh lamp [local] idle
This is user richardh on database lamp connecting locally with no query
in action.
Now, if the processor-time-used column is increasing rapidly that would
be unusual, but it should be running always.
> I think this cause the application slowing down
You haven't provided any convincing evidence of this - not yet.
> and sometimes this process make the server slowing down and I have to
> restart postmaster.
This should not be required. Ever.
> Is there somebody who experience the same problem? and what is the solution?
You'll need to work through the following steps:
1. Check there is nothing in the logs (messages/httpd/postgresql) that
looks "bad" when the application is slow.
2. Check your configuration settings for apache/postgresql - make sure
they are reasonable for the workload. If you're not sure what settings
you want for postgresql, perhaps read the performance tuning article here:
http://www.varlena.com/varlena/GeneralBits/Tidbits/index.php
3. Check the output of "vmstat 1" when the server is busy and see what
happens as it gets less busy. Especially check the disk i/o readings, as
this is frequently the limiting factor in a database system.
Once you have a good idea of what is happening, post again and we'll see
how we can help.
--
Richard Huxton
Archonet Ltd