Re: statement caching proof of concept - Mailing list pgsql-jdbc

From Dave Cramer
Subject Re: statement caching proof of concept
Date
Msg-id BCA6670E-411A-40B0-9331-51EDC6B7A44E@fastcrypt.com
Whole thread Raw
In response to Re: statement caching proof of concept  (Oliver Jowett <oliver@opencloud.com>)
Responses Re: statement caching proof of concept  (Mark Lewis <mark.lewis@mir3.com>)
Re: statement caching proof of concept  (till toenges <tt@kyon.de>)
Re: statement caching proof of concept  (Oliver Jowett <oliver@opencloud.com>)
List pgsql-jdbc
On 19-Jun-06, at 7:15 PM, Oliver Jowett wrote:

> Dave Cramer wrote:
>> This is just proof of concept. More work has to be done to make it
>> build properly and work properly under different jdk's
>
> Isn't there a bunch of statement state (things like fetch size, max
> rows, etc) that have defined defaults and this cache implementation
> will not provide?

Good point, these would all have to be reset to their defaults as well.

>
> The "wrapper" implementation approach suffers from the usual
> difficulty that the "back links" such as ResultSet.getStatement()
> point to the wrong object. It's actually quite a bit of work to get
> this right..
Since result sets only live as long as the statement, wouldn't they
point to the statement that is still open ?
>
> The cached statements are vulnerable to buggy apps that mutate the
> statement after close, since there's no interception of those
> methods to check whether the wrapper statement has been closed.

No question, and I would certainly not make this the default
behaviour. The user would have to turn on caching.
>
> What exactly is the performance bottleneck you're trying to avoid
> by having the statement pool? If it's the parse/plan cost, I think
> Mark's suggestion of putting the cache at the protocol level may be
> simpler. If it's overall statement cost, you might be better off
> with a generic wrapper that is not postgresql-specific at all.

How does the generic wrapper solve the problems above ? I would think
they all suffer from the same problems ?
>
> -O
>


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