Hello,
On Wed, Aug 13, 2014 at 5:28 PM, Marti Raudsepp <marti@xxxxxxxxx> wrote:
On Wed, Aug 13, 2014 at 9:44 AM, Albe Laurenz <laurenz.albe@xxxxxxxxxx> wrote:No need, wal_buffers is automatically tuned now. If your
> Set wal_buffers to 16MB so that a whole WAL segment will fit.
shared_buffers is 512MB or larger, wal_buffers will be 16MB.
Thanks everyone,
The settings that seem to work well for our workload/hw are
shared_buffers = 2GB
wal_buffers = 16MB
effective_cache_size = 100GB
checkpoint_segments = 32
* With shared_buffers set to default and wal_buffers set to 16MB - bgwriter stats indicates most writes were due to backend_buffers and not checkpoint buffers
* With shared_buffers set to 2GB and wal_buffers set to 16MB - bgwriter stats indicates most writes were due to checkpoint_buffers and not backend buffers
* Increasing wal_buffers beyond 16mb did not show any improvements
I also found good advice about shared_buffers and wal_buffers on this slides : http://2ndquadrant.com/media/pdfs/talks/MonitoringBufferCache.pdf
Few aspects that iam confused about are -
a. what is the relation between shared_buffers and wal_buffers when wal_buffers is set manually ?
b. What else is shared_buffers used for ?
c. Why does increasing shared_buffers to 2GB from default while leaving wal_buffers constant at 16MB increase checkpoint buffer writes ?
tia
dushy
