Re: [GENERAL] Slow PITR restore

From: Gregory Stark <stark(at)enterprisedb(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <josh(at)agliodbs(dot)com>, <pgsql-hackers(at)postgresql(dot)org>, "Heikki Linnakangas" <heikki(at)enterprisedb(dot)com>, "Simon Riggs" <simon(at)2ndquadrant(dot)com>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, "Jeff Trout" <threshar(at)threshar(dot)is-a-geek(dot)com>, "Koichi Suzuki" <suzuki(dot)koichi(at)oss(dot)ntt(dot)co(dot)jp>
Subject: Re: [GENERAL] Slow PITR restore
Date: 2007-12-14 01:09:21
Message-ID: 87prxam69q.fsf@oxford.xeocode.com
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"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> The argument that Heikki actually made was that multiple parallel
> queries could use more of the I/O bandwidth of a multi-disk array
> than recovery could. Which I believe, but I question how much of a
> real-world problem it is. For it to be an issue, you'd need a workload
> that is almost all updates (else recovery wins by not having to
> replicate reads of pages that don't get modified) and the updates have
> to range over a working set significantly larger than physical RAM
> (else I/O bandwidth won't be the bottleneck anyway). I think we're
> talking about an extremely small population of real users.

Of course that describes most benchmarks pretty well...

I think of this as a scalability problem, not so much a sheer speed problem.
If Postgres isn't fast enough for you you should be able to buy a faster
processor or faster disk or faster something to run it faster. The problem
with this situation is that buying a faster raid controller doesn't help you.

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
Ask me about EnterpriseDB's RemoteDBA services!

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