Re: Performance Problem between Ora 10g and Psql

Hello!

We're facing a performance problem here in a Oracle 10g -> PostgreSQL
environment. The Oracle DB accesses the PostgreSQL DB via UnixODBC +
psqlODBC.

There are some 100 records on the Oracle DB to be updated with data
obtained from a view of the PostgreSQL DB. The fetched data accumulates to
a few kB's and the update takes some 5 - 7 hours. During this time the
PostgreSQL machine is running at approx. 100% CPU usage.
If a select for the same data is issued from the Oracle DB the statement is
executed in half a second.

Is this the correct place to issue this problem?

How can I trace down the cause for this performance problem?

Thanx in advance!

Regards,
Thomas Radnetter

p.s. Mr. Ludek Finstrle, can you help again?

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Thomas,

On 7/12/06, Thomas Radnetter <tr75(at)gmx(dot)net> wrote:
> Is this the correct place to issue this problem?

It is if your issue is due to a PostgreSQL performance problem.

> How can I trace down the cause for this performance problem?

The first thing to do is to determine if it is a problem due to the
Oracle -> ODBC -> PostgreSQL thing or if it is a problem with the
query. My advice is to set log_min_duration_statement to 0 in your
postgresql.conf (and set the logger so that you can see the log output
somewhere). Then you'll see if your query is slow.

If your query is slow, post the output of an explain analyze on the
list with all the relevant information (structure of the concerned
tables, indexes, size...).

If not, it's probably more an ODBC problem.

Regards,

--
Guillaume Smet
Open Wide

On Wednesday 12 July 2006 01:33, Thomas Radnetter wrote:
> Hello!
>
> We're facing a performance problem here in a Oracle 10g -> PostgreSQL
> environment. The Oracle DB accesses the PostgreSQL DB via UnixODBC +
> psqlODBC.
>
> There are some 100 records on the Oracle DB to be updated with data
> obtained from a view of the PostgreSQL DB. The fetched data accumulates to
> a few kB's and the update takes some 5 - 7 hours. During this time the
> PostgreSQL machine is running at approx. 100% CPU usage.
> If a select for the same data is issued from the Oracle DB the statement is
> executed in half a second.
>
> Is this the correct place to issue this problem?

Sure but you haven't provided a TON of information that would be needed to
help?

If you execute the same query that is being executed via ODBC, via psql is the
performance problem still there?

If so, you probably have a postgresql issue, otherwise look at Oracle or ODBC.

If it is a PostgreSQL issue:
Do you have indexes applied?
What is the explain plan?
When was the last time you analyzed?
What about vacuum?

etc. etc.

Sincerely,

Joshua D. Drake

>
> How can I trace down the cause for this performance problem?
>
> Thanx in advance!
>
> Regards,
> Thomas Radnetter
>
> p.s. Mr. Ludek Finstrle, can you help again?
>
> --
>
> "Feel free" &ndash; 10 GB Mailbox, 100 FreeSMS/Monat ...
> Jetzt GMX TopMail testen: http://www.gmx.net/de/go/topmail

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