Re: Prepared statements and suboptimal plans

On 21/09/2011 7:27 AM, Royce Ausburn wrote:
> Hi all,
>
> It looks like I've been hit with this well known issue.  I have
> a complicated query that is intended to run every few minutes, I'm
> using JDBC's Connection.prepareStatement() mostly for nice
> parameterisation, but postgres produces a suboptimal plan due to its
> lack of information when the statement is prepared.
>
> [snip]
>
> We've been worst hit by this query on an 8.3 site.  Another site is
> running 8.4.  Have there been improvements in this area recently?
>  Upgrading to 9.0 might be viable for us.

Tom just mentioned that 9.1 will be able to re-plan parameterized
prepared statements, so this issue will go away. In the mean time you
can only really use the standard workaround of setting the prepare
theshold to 0 to disable server-side prepare, so you can continue to use
JDBC prepared statements and have the driver do the parameter
substitution for you.

--
Craig Ringer