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Posted to user@jmeter.apache.org by welp <pe...@trivadis.com> on 2009/07/29 12:56:07 UTC
Using literals with JDBC the sampler instead of bind variables
Hoi again,
for some JDBC tests, I need to send the same query with different filters
(where conditions) against an Oracle database. usually, I would use the
"prepared select statement" query type for that using bind variables. But
for the Oracle Query Optimizer it can be a big difference when calculating
its execution plan if I use Bind Variables or if I use literals. Example:
select count(*) from v_whatever where xyz = ? -- (with ? replaced by 4711
when preparing the statement)
or
select count(*) from v_whatever where xyz = 4711
... can lead to very different executions plans and therefore also lead to
very different response times. Usually the execution plan that I get when
using literals (4711 directly instead of a ? in the prepared statement) is
often better - even Oracle completely needs to hard-parse the statement with
the literal - for long running queries in data warehouses, using literals
can lead to faster responses.
Hence I need to test it with literals but I want to get the literals from a
CSV file and not hard-code it into multpile JDBC samplers.
Is there a way to do this?
Thanks a lot in advance!
Regards
Peter
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Re: Using literals with JDBC the sampler instead of bind variables
Posted by welp <pe...@trivadis.com>.
sebb-2-2 wrote:
>
> Yes - just use CSV Dataset and code as follows:
>
> select count(*) from v_whatever where xyz = ${NUMBER} and name="${NAME}"
>
> Note that you need to add quotes for strings.
>
Thanks a lot!
Sometimes, it's so easy :)
Cheers
Peter
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Re: Using literals with JDBC the sampler instead of bind variables
Posted by sebb <se...@gmail.com>.
On 29/07/2009, welp <pe...@trivadis.com> wrote:
>
> Hoi again,
>
> for some JDBC tests, I need to send the same query with different filters
> (where conditions) against an Oracle database. usually, I would use the
> "prepared select statement" query type for that using bind variables. But
> for the Oracle Query Optimizer it can be a big difference when calculating
> its execution plan if I use Bind Variables or if I use literals. Example:
>
> select count(*) from v_whatever where xyz = ? -- (with ? replaced by 4711
> when preparing the statement)
> or
> select count(*) from v_whatever where xyz = 4711
>
> ... can lead to very different executions plans and therefore also lead to
> very different response times. Usually the execution plan that I get when
> using literals (4711 directly instead of a ? in the prepared statement) is
> often better - even Oracle completely needs to hard-parse the statement with
> the literal - for long running queries in data warehouses, using literals
> can lead to faster responses.
>
> Hence I need to test it with literals but I want to get the literals from a
> CSV file and not hard-code it into multpile JDBC samplers.
>
> Is there a way to do this?
Yes - just use CSV Dataset and code as follows:
select count(*) from v_whatever where xyz = ${NUMBER} and name="${NAME}"
Note that you need to add quotes for strings.
> Thanks a lot in advance!
> Regards
> Peter
>
> --
> View this message in context: http://www.nabble.com/Using-literals-with-JDBC-the-sampler-instead-of-bind-variables-tp24716871p24716871.html
> Sent from the JMeter - User mailing list archive at Nabble.com.
>
>
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> To unsubscribe, e-mail: jmeter-user-unsubscribe@jakarta.apache.org
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>
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