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From "Patrick Linskey" <plins...@bea.com>
Subject RE: Cache with two ConnectionFactories?
Date Thu, 08 Feb 2007 06:33:26 GMT
There are a lot of things that you could do. The simplest, and least
cache-effective, would be to have two different EMFs that each have
their own caches. These caches could be linked together (using the sjvm
remote commit provider), so that data would stay consistent, but
otherwise, this would be like using different databases.

If you can access the same data via both data sources, the other option
would be to create your own data source that uses a ThreadLocal or
something to decide which underlying data source to use, and tell
OpenJPA to use that data source. Then, depending on the use case, you
could select a different data source.

Or, if the only thing that you need is different connection credentials
when logging in, you could use a single data source and call
EMF.createEntityManager(Map) with openjpa.ConnectionUserName and
openjpa.ConnectionPassword key-value pairs in the map.

Hope that helps,

-Patrick

-- 
Patrick Linskey
BEA Systems, Inc. 

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> -----Original Message-----
> From: Don Brady [mailto:dbrady@pobox.com] 
> Sent: Wednesday, February 07, 2007 4:59 PM
> To: open-jpa-dev@incubator.apache.org
> Subject: Cache with two ConnectionFactories?
> 
> I could not figure this out in reading the OpenJPA documentation.
> 
> We have just the one database and set of tables, but we need 
> to have two 
> separate Connection Pools to the same database in order to have two 
> different userid's.
> 
> (We want to set the priorities on the database differently 
> for access by 
> the two different usernames).
> 
> One is to be used for updates and short queries, and the other for 
> queries expected to give large result sets.
> 
> In these circumstances, is it possible to use the Data Cache and the 
> Query Cache?
> 
> I am worried that if a new entity / data row is created in the Data 
> Cache under one userid/pool/connectionFactory, it will not show up in 
> the Query Cache for the other userid/pool/connectionFactory 
> if a query 
> is done.
> 
> Thanks and if this is off-topic please let me know.
> 
> Maybe the thing to do would be to have a cache enabled for the 
> userid/pool/connectionFactory used for short queries and 
> updates, but no 
> cache for the userid/pool/connectionFactory?
> 
> Don
> 

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