Re: PGStatement#setPrepareThreshold - Mailing list pgsql-jdbc

Csaba,

Actually I was debugging some other code and noticed that it doesn't
really get set, this just confirms my suspicions. I'll try to get
something out in a few hours

Dave
On 3-Aug-06, at 5:17 AM, Csaba Nagy wrote:

> Oliver,
>
> Thanks for your answer.
>
>> The logic looks like:
>> - On statement creation set count=0
>> - On each execution:
>>    - If this statement is a PreparedStatement, increment count
>>    - If threshold == 0 or count < threshold, make this execution
>> "oneshot"
>>    - Execute query
>
> OK, I've checked the sources. I'm using postgresql-jdbc-8.1dev-400.
> The relevant piece of code looks to me to be in
> AbstractJdbc2Statement#execute(Query,ParameterList,int):
>
>         // Only use named statements after we hit the threshold
>         if (preparedQuery != null)
>         {
>             ++m_useCount; // We used this statement once more.
>             if (m_prepareThreshold == 0 || m_useCount <
> m_prepareThreshold)
>                 flags |= QueryExecutor.QUERY_ONESHOT;
>         }
>
> So if preparedQuery is not null for prepared statements, it should
> work
> as you said...
>
>> "oneshot" queries use the unnamed statement (with one exception:
>> queries
>> that will be backed by a portal use a named statement)
>>
>>> I couldn't figure out this from the log files... postgres logs the
>>> queries as <unnamed>, but that doesn't tell me too much.
>>
>> If you're seeing <unnamed> then those queries aren't using server-
>> side
>> prepare (the unnamed statement is also special as it's the trigger
>> for
>> the planner behaviour that you are trying to avoid..) .. so it seems
>> that you are not managing to trigger server-side prepare for some
>> reason. Maybe you are using a plain Statement?
>
> No, I definitely use a prepared statement, I have lots of
> parameters in
> the IN clause... that's part of the problem. And I checked again,
> and it
> is logged as <unnamed> in the postgres logs.
>
> So the only remaining suspect is that the threshold is not really
> set to
> 1. This is somewhat strange, as I use a connection pool and set it
> to 1
> on each connection, and only set it to 0 on specific statements
> where I
> do want the parameter values to be taken into account (I know, I'll
> have
> to change this, but it was the easiest way to get the system stable
> after switching from Oracle to postgres).
>
> I will have to investigate what is the real problem.
>
> Thanks,
> Csaba.
>
>
>
>
>
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