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Groups > comp.lang.java.databases > #599

Re: Query performance

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thomas.lehmann@adtech.com, 05.04.2013 13:16:
> Hi,
>
> using a very simple Java application I've connected to a database that
> is Oracle. The code just uses standard JDBC handling like Connection,
> Statement and ResultSet.
>
> Now ...
>
> A very specific SQL statement takes about 250ms just providing an ID.
> Using "SQuirrel" or "SQL Plus" as clients exactly the same query takes 5ms.
>
> SQuirrel is in Java and - so far I have seen - the same JDBC handling
> has been taken as I did. For Squirrel to say: I have been using the
> same Oracle (thin) driver and same connection parameter (for sure).
>
> So what might be the reason for the performance problem?
>

I assume in Squirrel or SQL*PLus you are using literals for your statement parameters.

Inside your code you are probably using bind variables - which can lead to completely different execution plans.


To confirm this theory, you need to do an explain with and without bind variables:

explain plan for select * from foo where id = ?;

vs.

explain plan for select * from foo where id = 42;

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Query performance thomas.lehmann@adtech.com - 2013-04-05 04:16 -0700
  Re: Query performance "John B. Matthews" <nospam@nospam.invalid> - 2013-04-05 09:30 -0400
  Re: Query performance David Kerber <dkerber@WarrenRogersAssociates.invalid> - 2013-04-11 08:18 -0400
  Re: Query performance Roedy Green <see_website@mindprod.com.invalid> - 2013-04-15 11:58 -0700
    Re: Query performance Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-15 22:05 +0000
      Re: Query performance Arne Vajhøj <arne@vajhoej.dk> - 2013-04-15 21:14 -0400
    Re: Query performance Arne Vajhøj <arne@vajhoej.dk> - 2013-04-15 21:12 -0400
    Re: Query performance Lew <lewbloch@gmail.com> - 2013-04-15 19:01 -0700
  Re: Query performance Martin Gregorie <martin@address-in-sig.invalid> - 2013-04-15 21:39 +0000
  Re: Query performance Arne Vajhøj <arne@vajhoej.dk> - 2013-04-15 21:18 -0400
  Re: Query performance Harry Tuttle <SOZRBLNTLEEE@spammotel.com> - 2013-04-16 14:59 +0200

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