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help / color / mirror / Atom feedFrom: Purav Chovatia <[email protected]>
To: [email protected]
Subject: 99% time spent in WAL wait events
Date: Mon, 16 Oct 2017 19:04:36 +0530
Message-ID: <CADrzpjE7RZtPjEWQYitaRo5wjfVTy02LhAbDsgCk43WxPH=acA@mail.gmail.com> (raw)
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Hello,
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
Regards
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