RE : Remote query very slow

Thanks for your answer.
It seems that my problem lie on the not use of Statement.setFetchSize
and the use of the heap.

In fact, it appears that when I select all the fields, it's very slow
but when I select only the PK it's already better. So it seems that the
driver is waiting for the whole data and, only then, returns.

I should investigate in that way.

Last question, I'm using pgAdminIII to perform my queries. I think that
I should have the same problem on the server side than on the remote
machine as it is using the same driver. Am I wrong on that point?

Thanks a lot

-----Message d'origine-----
De : pgsql-jdbc-owner(at)postgresql(dot)org
[mailto:pgsql-jdbc-owner(at)postgresql(dot)org] De la part de Oliver Jowett
Envoyé : jeudi 30 septembre 2004 23:55
À : Johann Robette
Cc : pgsql-jdbc(at)postgresql(dot)org
Objet : Re: [JDBC] Remote query very slow

Johann Robette wrote:

> I’ve installed postgres 7.3.5 on a fedora server. It works fine, at
> least on a local basis. I perform an easy select * from a table and I
> get the answer in approximatively 1s.
>
> Now, I used the jdbc driver (jdbc3) for postgres. It connects fine
but,
> performing the same query, I get the answer in 7s.
>
> What could be my problem?

Is it really a "remote query" problem? Or is it just a difference
between using psql and JDBC? How fast is the query if you run it
"remotely" via psql? (psql -h server database)

GC is the most likely culprit if you are running with default heap
settings and a large data set. Without instructions to the contrary
(e.g. Statement.setFetchSize) the driver will try to pull the entire
resultset into heap before returning from query execution. Try turning
on -verbose:gc on your JVM and see how much time is spent doing GC.

You probably want to upgrade both your server and JDBC driver (assuming
you're using the 7.3-era driver) if you can. The 7.3 server is getting
quite old now, and there are a lot of bugfixes in the current driver
that aren't in the 7.3 JDBC driver.

-O

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