From: fkater@googlemail.com <fkater@googlemail.com>
To: Florian Weimer <fweimer@bfk.de>
Cc: pgsql-performance@postgresql.org
Subject: Re: Inserting 8MB bytea: just 25% of disk perf used?
Date: Thu, 14 Jan 2010 22:27:19 +0100
Message-ID: <20100114212719.GE2384@comppasch2> (raw)
In-Reply-To: <82aawgoh09.fsf@mid.bfk.de>
References: <20100114142903.GB2973@comppasch2>
<82aawgoh09.fsf@mid.bfk.de>
Florian Weimer:
> > Do you have any further idea why 16MB/s seems to be the limit here?
>
> BYTEA deserialization is very slow, and this could be a factor here.
> Have you checked that you are in fact I/O bound?
Could you elaborate that a bit? It sounds interesting but I
do not get what you mean by:
"bytea deserialization": Do you mean from an escaped string
back to real binary data? Does that apply to my case (I use
PGexecParam and have the Format arg set to 1, binary) ?
"I/O bound": What do you mean by that?
> You can speed things up by sending the data in binary, by passing
> approriate parameters to PQexecParams().
Do you mean the Format arg =1 ? If not, what is appropriate
here?
Felix
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To: pgsql-performance@postgresql.org
Cc: fkater@googlemail.com, fweimer@bfk.de
Subject: Re: Inserting 8MB bytea: just 25% of disk perf used?
In-Reply-To: <20100114212719.GE2384@comppasch2>
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