From: Pin007 <pin007@gmail.com>
To: Merlin Moncure <mmoncure@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Streaming replication performance
Date: Tue, 16 Aug 2011 22:03:16 +0200
Message-ID: <201108162203.16635.pin007@gmail.com> (raw)
In-Reply-To: <CAHyXU0zCVv24bzEeM8rANLK3ZyGo2VO43DS0ZwomNfkn9GsfTA@mail.gmail.com>
References: <201108111646.39321.pin007@gmail.com>
<CAHyXU0zCVv24bzEeM8rANLK3ZyGo2VO43DS0ZwomNfkn9GsfTA@mail.gmail.com>
Dne Pá 12. srpna 2011 18:47:24 Merlin Moncure napsal(a):
> On Thu, Aug 11, 2011 at 9:46 AM, Antonin Faltynek <pin007@gmail.com> wrote:
> > Hi all,
> >
> > I'm testing Streamin replication with one hot standby node and I'm
> > experiencing high delay of hot standby node.
> >
> > When I reach aprox. 50 transactions per second where every transaction
> > includes only simple "UPDATE status SET number = number + 1 WHERE name =
> > 'iterations'", the standby server falls behind master and the delay is
> > several minutes. In comparison, Slony1 have no issues with the same test
> > and its delay is only several seconds.
> >
> > Am I missing some configuration that affects speed of streaming
> > replicaiton?
>
> hm -- how are you determining the standby is behind? are you running
> any other queries on the standby?
>
> merlin
Simply, during test I'm generating series of numbers that I'm periodicaly
checking on both master and stand by server.
Also I'm measuring several server metrics, like CPU usage, disk usage, network
bandwidth.
When testing streaming replication network usage does not get over 1Mbps and
catching master takes several tens of minutes, while during test of WAL file
shipping, network usage get to 3-5Mpbs and stand by server does not fall
behind master more than several seconds.
There is no other traffic on stand by server, only periodical check of test
table (SELECT * FROM status) every 2s. Extension of this check interval does
not affect behavior of streaming replication.
Tonda
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To: pgsql-performance@postgresql.org
Cc: pin007@gmail.com, mmoncure@gmail.com
Subject: Re: Streaming replication performance
In-Reply-To: <201108162203.16635.pin007@gmail.com>
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