Re: UPDATES hang every 5 minutes

On Thu, 9 Aug 2007, Marc Rossi wrote:

> as well as made changes to the bgwriter settings as shown below (taken
> from a post in the pgsql-performance list)
>bgwriter_lru_percent = 20.0             # 0-100% of LRU buffers scanned/round
>bgwriter_lru_maxpages = 200             # 0-1000 buffers max written/round
>bgwriter_all_percent = 10.0             # 0-100% of all buffers scanned/round
>bgwriter_all_maxpages = 600             # 0-1000 buffers max written/round

Be warned that these are settings from a much more powerful server than it
sounds like you have, and I wouldn't be surprised to find your average
performance tanks as a result.  Making the background writer this
aggressive will waste a lot of I/O, and unless you've got a lot of spare
I/O to waste (which was the case on the source of this tuning) it can make
your problem worse.  I'd hesitate to recommend setting either percentage
over 5% or either maxpages>100 as a first step on a production system.
You may be in for a bad day tomorrow.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD