Re: meta data information returned for domains

From: Kris Jurka <books(at)ejurka(dot)com>
To: Iain <iain(at)mst(dot)co(dot)jp>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: meta data information returned for domains
Date: 2004-12-06 10:44:02
Message-ID: Pine.BSO.4.56.0412060536420.4347@leary.csoft.net
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On Mon, 6 Dec 2004, Iain wrote:

> I expect this question has been asked before but is there any reason why I
> shouldn't use the newer driver (for v8) with 7.4.6? I assume that it would
> allow me to use the getUDT method if I did that.
>

There are potentially serious performance problems with using the 8.0
driver on a 7.4 server. The 8.0 driver uses a server prepared statement
for every PreparedStatement object. On the server side prepared
statements usually don't consider the actual parameter values to generate
a query plan. This means an inferior query plan can be generated when the
parameter values are known, but unused, and you don't intend to reuse the
prepared statement. The 8.0 server has a mechanism to use parameter
values for planning in certain situations that the 7.4 server does not.

Kris Jurka

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