Re: Delaying the planning of unnamed statements until Bind

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От Oliver Jowett
Тема Re: Delaying the planning of unnamed statements until Bind
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Msg-id 40BA63F7.80001@opencloud.com
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Ответ на Re: Delaying the planning of unnamed statements until Bind  (Heikki Linnakangas <hlinnaka@iki.fi>)
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Heikki Linnakangas wrote:

> I'm worried about plan stability if we enable it by default. It could
> lead to nasty, hard to reproduce performance problems. Think about this
> scenario:

This is my main concern with the approach Tom suggested.

> Also keep in mind that at least some application servers have a
> client-side prepared statement cache, so that even if the application
> used a non-prepared statement for the reports, the middleware prepares it
> anyway.

It's less of an issue if we only use this behaviour when binding the 
unnamed statement. The unnamed statement is quite "special" and is 
unlikely to be reused accidentally (for one thing, you can only have one 
unnamed statement..)

The patch I posted to -patches earlier uses this approach.

-O


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