Re: Inserting 8MB bytea: just 25% of disk perf used? - Mailing list pgsql-performance

From Florian Weimer
Subject Re: Inserting 8MB bytea: just 25% of disk perf used?
Date
Msg-id 82hbqnkd7a.fsf@mid.bfk.de
Whole thread Raw
In response to Re: Inserting 8MB bytea: just 25% of disk perf used?  ("fkater@googlemail.com" <fkater@googlemail.com>)
List pgsql-performance
> 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?

Yes, that is what I meant.

> Does that apply to my case (I use PGexecParam and have the Format
> arg set to 1, binary) ?

Yes, this was my suggestion.  There is probably some other issue,
then.

> "I/O bound": What do you mean by that?

You should check (presumably using the Windows performance monitoring
tools, but I'm not familiar with Windows) if the PostgreSQL process is
indeed waiting on disk I/O.

--
Florian Weimer                <fweimer@bfk.de>
BFK edv-consulting GmbH       http://www.bfk.de/
Kriegsstraße 100              tel: +49-721-96201-1
D-76133 Karlsruhe             fax: +49-721-96201-99

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