On Wed, Feb 6, 2013 at 7:49 AM, Kevin Grittner <kgrittn@xxxxxxxxx> wrote:
"ac@xxxxxx" <ac@xxxxxx> wrote:
> Johnny Tan <johnnydtan@xxxxxxxxx> wrote:
>>shared_buffers = 48GB# min 128kB
> From the postgresql.conf, I can see that the shared_buffers isI have seen symptoms like those described which were the result of
> set to 48GB which is not small, it would be possible that the
> large buffer cache could be "dirty", when a checkpoint starts, it
> would cause a checkpoint I/O spike.
>
>
> I would like to suggest you about using pgtune to get recommended
> conf for postgresql.
too many dirty pages accumulating inside PostgreSQL shared_buffers.
It might be something else entirely in this case, but it would at
least be worth trying a reduced shared_buffers setting combined
with more aggressive bgwriter settings. I might try something like
the following changes, as an experiment:
shared_buffers = 8GB
bgwriter_lru_maxpages = 1000
bgwriter_lru_multiplier = 4
Thanks Kevin. Wouldn't this be controlled by our checkpoint settings, though?
