Re: Stalled post to pgsql-bugs
Ok. There is a problem with the patches that went in between Postgres
9.4.3->9.4.4
I downgraded to Postgres 9.4.3 and everythig is normal. "Actual disk
writes" in iostat is pretty much as "Total disk writes" (between 50-100
Kbps and not in Mbps). "vmstat 1" also shows no excessive disk writes.
I am using postgres 9.4.3 on Gentoo linux along with uwsgi, python 2.7 and
nginx.
-Sushant.
On Thu, Jul 23, 2015 at 10:27 AM, <pgsql-bugs-owner@postgresql.org> wrote:
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pgsql-bugs-owner@postgresql.org---------- Forwarded message ----------
From: sushant@indiankanoon.com
To: pgsql-bugs@postgresql.org
Cc:
Date: Thu, 23 Jul 2015 04:56:17 +0000
Subject: BUG #13515: Much higher disk writes after postgres upgrade
9.4.3->9.4.4
The following bug has been logged on the website:Bug reference: 13515
Logged by: Sushant Sinha
Email address: sushant@indiankanoon.com
PostgreSQL version: 9.4.4
Operating system: Linux
Description:After upgrade from postgres 9.4.3 to 9.4.4 I am seeing constant disk writes
of 4-8MB/s in the background in production. I verified it using iotop and
vmstat. iotop shows "Total Disk Write" to be minuscule (like 10-100Kbps).
It
is affecting runtime performance. I never noticed this issue with postgres
9.4.3.I increased the shared buffers from 128MB to 1GB and still didn't see any
benefit.The website (http://indiankanoon.org) mostly uses text search with gin
index
and some logging of click through data. The main database is replicated
using "streaming asynchronous replication".I am going to downgrade it to 9.4.3 to see if the upgrade was the real
problem. But just wanted to check if anyone else noticed it.
Import Notes
Reply to msg id not found: 5c4772f290a19c03da5668239986f1b1e076cd0a@postgresql.orgReference msg id not found: 5c4772f290a19c03da5668239986f1b1e076cd0a@postgresql.org
Sushant Sinha <sushant@indiankanoon.com> wrote:
On Thu, Jul 23, 2015 at 10:27 AM, <pgsql-bugs-owner@postgresql.org> wrote:
After upgrade from postgres 9.4.3 to 9.4.4 I am seeing constant disk writes
of 4-8MB/s in the background in production. I verified it using iotop and
vmstat. iotop shows "Total Disk Write" to be minuscule (like 10-100Kbps). It
is affecting runtime performance. I never noticed this issue with postgres
9.4.3.I increased the shared buffers from 128MB to 1GB and still didn't see any
benefit.The website (http://indiankanoon.org) mostly uses text search with gin index
and some logging of click through data. The main database is replicated
using "streaming asynchronous replication".I am going to downgrade it to 9.4.3 to see if the upgrade was the real
problem. But just wanted to check if anyone else noticed it.
Ok. There is a problem with the patches that went in between
Postgres 9.4.3->9.4.4I downgraded to Postgres 9.4.3 and everythig is normal. "Actual
disk writes" in iostat is pretty much as "Total disk writes"
(between 50-100 Kbps and not in Mbps). "vmstat 1" also shows no
excessive disk writes.
Did you notice whether it was an autovacuum process causing the
additional I/O in 9.4.4? There were some bugs in 9.4.3 that failed
to vacuum away old multi-transaction tracking structures in a
timely fashion, causing data loss and database corruption. Once
you upgraded a background task was probably trying to make up for
the lack of timely maintenance, so that you would not experience
those problems. Downgrading may be a little faster for a little
while, but you're almost certain to regret doing it very soon....
--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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