openjpa-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jeremy Bauer <>
Subject Re: CLOB loading - query per row
Date Tue, 07 Feb 2012 14:47:01 GMT
Hi Simon,

What database are you using?  Each DB/JDBC driver handles retrieving
lob data differently (although, that is continually getting better and
more standardized with new rev's of JDBC).  Some DBs allow inlining,
sometimes they requires a separate fetch or vendor specific API.
Normally, this via DB/driver specific code is isolated in the DB
dictionaries.  It is odd that OpenJPA is behaving differently with one
path vs. another, though.  Any chance you could post a very simple


On Mon, Feb 6, 2012 at 6:19 PM, Simon Droscher
<> wrote:
> Hi.
> Just wondering if anyone had encountered a similar issue to us with CLOB
> loading and/or can explain the behaviour:
> When we have entities with CLOB fields and do a EntityManager.get() of one
> of those objects, OpenJPA will load the CLOBs with the rest of the data as
> part of a single query. But when we load the same object using a named
> query, for example "SELECT t FROM Thing t WHERE t.code = ?1", OpenJPA
> generates a separate SQL query for each CLOB row after it has loaded the
> rest of the data for that object. We see this behaviour even when we are
> only querying for a single field of the object (not even the CLOB field).
> This is having a big impact on performance for us as it involves a lot more
> roundtrips to the DB.
> FYI we are running OpenJPA 1.2.1
> --
> View this message in context:
> Sent from the OpenJPA Users mailing list archive at

View raw message