Kindly ignore this post. It was an oversight - the wait times are in
millisec and hence even if we manage to reduce these waits to 0, we will
gain only 1000 msec of savings during a workload of 40min.


On 16 Oct 2017 7:04 pm, "Purav Chovatia" <> wrote:


We are running workload on a EDB Postgres Advanced Server 9.6 and we see
that 99% of the time is spent on WAL wait events:

*System Wait Information WAIT NAME COUNT WAIT TIME % WAIT
wal flush 564552 298.789464 41.67 wal write 521514 211.601124 29.51 wal
file sync 521546 205.519643 28.66*
Disk IO performance is not an issue and WAL is on a dedicated disk.

Can somebody pls suggest if there is any possibility to improve this & how?

We already tried wal_buffers=96m, wal_sync_method=open_sync/open_datasync,
checkpoint_completion_target=0.9 but none of those helped.

System has 32GB RAM and shared_buffers=8GB. All transactions are happening
on a single table which has about 1.5m records and the table size is 1.7GB
with just one PK index.

Many Thanks


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