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Re: Limit vs setMaxRows issue

From: Marc Herbert <Marc(dot)Herbert(at)continuent(dot)com>
To: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Limit vs setMaxRows issue
Date: 2006-07-10 08:51:21
Message-ID: khjd5cd4zcm.fsf@meije.emic.fr (view raw or flat)
Thread:
Lists: pgsql-jdbc
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> No, it would take a protocol change to add such a thing out-of-line
> (that is, not as a LIMIT clause in the query text).  The reason is that
> the planning is done at PARSE time, or at the latest BIND time.  The
> row limit field in the EXECUTE message comes far too late to affect the
> query plan. 


If planning is done at time of creation of the PreparedStatement
object (reminder: the example given above has no parameters), then the
setMaxRows() call will come too late whatever is the protocol change.
I mean: no protocol change can go back in time and "optimize" by not
doing useless work already done.

Thanks in advance for pointing out my mistake(s) here.


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