Re: Mutli-threading and performance of ODBC

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Stergios Zissakis" <szis(at)intranet(dot)gr>
Cc: pgsql-odbc(at)postgresql(dot)org, "Kostas Lykiardopoulos" <klyk(at)intranet(dot)gr>, "Dimitris Pantermalis" <dpant(at)intranet(dot)gr>
Subject: Re: Mutli-threading and performance of ODBC
Date: 2004-03-09 15:56:40
Message-ID: 25601.1078847800@sss.pgh.pa.us
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"Stergios Zissakis" <szis(at)intranet(dot)gr> writes:
> 1. Studing the postgreSQL log, it is apparent that the the ODBC driver
> switches off the Genetic Query Optimiser (geqo) and tries to switch on
> another optimiser called (ksqo) which fails. What is the ksqo optimiser?

ksqo was a hack that disappeared several releases back. I do not know
why ODBC still has a reference to it (or why it tried to force it on
in the first place; IMHO a driver has no business making that kind of
decision).

I would recommend removing both of those SETs from the driver code.

> 3. Also, using ODBC, in the log file of PostgreSQL, it is seen that a
> lot of blank statements are generated. Can these blank statements affect
> the performance?

The backend won't spend much time on a blank statement, but if a
separate network round trip is being incurred for each one, that could
get a tad expensive ...

regards, tom lane

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