I have tuned the checkpoint_timeout to 30 second which is ten times less than default and the issue is still reproduced. Do you have any recommended configuration for WAL ?
Ho Fat Tsang wrote: > > I am new for postgresql server. And now i work on a projects which > requires postgreSQL 8.0 and Java. I don't know why the server occasionally > slow down a bit for every 3 minutes.
> Do anyone can help me about this ? or any resolution for a sudden > performance degrade ( because the application i need to develop is quite > time-critical).
It's probably checkpointing. PG will write updates to the transaction log (WAL) immediately and update the main data files later. Every so often it makes sure the data files are up-to-date and this is called checkpointing.
You want checkpointing to happen more often, not less. That way the load will be less each time it happens. See the manual for details.