From: | "Arcadius A(dot)" <arcadius(at)menelic(dot)com> |
---|---|
To: | David Gagnon <dgagnon(at)siunik(dot)com> |
Cc: | pgsql-jdbc(at)postgresql(dot)org |
Subject: | Re: implementing asynchronous notifications PLEASE CONFIRM MY |
Date: | 2005-08-29 03:34:02 |
Message-ID: | 4312822A.8030007@menelic.com |
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Thread: | |
Lists: | pgsql-jdbc |
David Gagnon wrote:
> Hi ,
>
> Thanks for your answer, see my answer below..
>
>> David Gagnon wrote:
>>
>>> Hi all,
>>
[...]
>>
>> However I do not know your exact requirement, if I were to solve such
>> a problem, I would not try to put any overhead on the DB server;
>> after all, the purpose of caching is to give a brake to the DBServer.
>>
>> In fact, the easiest way to have the cache in sync with the DB is to
>> have a kind of Facade , a unique class, with static methods for
>> reading/writing data for both the cache and the DB.
>>
>> Using a single class for reading/writing , you won't need the DB to
>> notify you of changes since all call go through your facade, that
>> means that you know when things are being changed and can take action.
>>
>> However, your requirements my be different.
>>
>>
>> Regards. \
>
>
[...]
> The big problem is that when a user launch a stored procedure.. chance
> are that he will consult the other data right after the completion of
> the stored procedure. If data have not been updated in the cache I
> will display invalid data :-(
>
If the user is calling the SP from the same Java app , then , what I
said before is still valid.
The method which calls the SP should clear/invalidate the cache .
So, the next time the user tries to view data, as the cache is
empty/invalidated , new stuff should be loaded from the DB.
Regards.
Arcadius.
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