Thanks a lot for your advice. I found the difference: My Java program sends one huge SQL string containing 1000 INSERT
statementsseparated by ';' (without using prepared statements at all!), whereas my C++ program sends one INSERT
statementwith parameters to be prepared and after that 1000 times parameters. Now I refactured my C++ program to send
also1000 INSERT statements in one call to PQexec and reached the same performance as my Java program.
I just wonder why anyone should use prepared statements at all?
> -----Ursprüngliche Nachricht-----
> Von: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-
> owner@postgresql.org] Im Auftrag von Richard Huxton
> Gesendet: Donnerstag, 16. Dezember 2010 13:15
> An: Werner Scholtes
> Cc: Divakar Singh; pgsql-performance@postgresql.org
> Betreff: Re: [PERFORM] performance libpq vs JDBC
>
> On 16/12/10 09:21, Werner Scholtes wrote:
> > I assume that the wire protocol of PostgreSQL allows to transmit
> > multiple rows at once, but libpq doesn't have an interface to access
> it.
> > Is that right?
>
> Sounds wrong to me. The libpq client is the default reference
> implementation of the protocol. If there were large efficiencies that
> could be copied, they would be.
>
> Anyway - you don't need to assume what's in the protocol. It's
> documented here:
> http://www.postgresql.org/docs/9.0/static/protocol.html
>
> I'd stick wireshark or some other network analyser on the two sessions
> -
> see exactly what is different.
>
> --
> Richard Huxton
> Archonet Ltd
>
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