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Date: Wed, 23 Dec 2009 08:49:27 -0800 (PST)
From: StevenK <sdkuker@gmail.com>
To: users@openjpa.apache.org
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 <1261578107625-4208800.post@n2.nabble.com>
Subject: Re: FetchGroups and Embeddable Fields
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We created an entity that contained some embedded fields and some
non-embedded fields (string, ints, etc).  All fields are lazy loaded (the
default).  We created a fetch plan that includes a couple of embedded fields
and a couple of non-embedded fields.  We then created a query that uses the
fetch plan.  

 We created a test that added a number of these entities to the database. 
We then looped through all the entities that were returned by the query and
accessed each field.  We turned sql tracing on so we could see what sql was
generated and executed.   What we found was that when we accessed the
non-embedded fields, no sql was executed (we expected this because these
fields were included in the fetch plan).  When we accessed the embedded
fields sql was executed (selects for those fields) indicating that the
fields were still being lazy loaded and the fetch plan was not eagerly
loading the data.  We did not expect this as these fields were also part of
the fetch plan.

Have you worked with fetch plans that combined embedded and non-embedded
fields?  Any idea what might be causing this?

Thanks for your help.

Pinaki Poddar wrote:
> 
>> Are their any restrictions, constraints, or other complications that
>> anyone is aware of?
> Nothing specific comes to mind. Are you seeing any anomaly w.r.t. embedded
> fields in a fetch plan?
>  
> 
> StevenK wrote:
>> 
>> I am trying to optomize a query by using fetch groups.  One of the fields
>> I'd like to include in the group is an embedded entity.  When I turn sql
>> tracing on, run my query, and then display the value of the fields that
>> were returned, I can see that the non-embedded fields in my entry display
>> without additional selects from the database - which is exactly what I
>> expect.  The embedded fields however generate a select to the database to
>> get their contents - which I am trying to avoid by including those fields
>> in the fetch group.  Has anyone else worked with fetch groups and
>> embedded fields?  Are their any restrictions, constraints, or other
>> complications that anyone is aware of?
>> 
>> Thanks!
>> 
> 
> 

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