James,
There is no query hint to do this, feel free to log an enhancement request for this.
done
You can configure this using the ReadAllQuery code API.
I'll give it a try, thank you
Kate Lain wrote: > > James, > > I have three related entities say A, B, C with an OneToMany mapping both > between A - B and A - C . There is a need to read all the objects in a > single query. Therefore i've defined a named query in A as
follows: > > @NamedQuery( > name = "A.findAll", > query = "SELECT a FROM A a , > hints = { > @QueryHint(name = QueryHints.BATCH, value = "a.bs"), > @QueryHint(name = QueryHints.BATCH, value = "a.cs"), > @QueryHint(name = QueryHints.JDBC_FETCH_SIZE, value = "500") > } > ) > > As result I got about 500 objects for A, 5000 objects for B and 50000 > objects for C from the three queries (the one named and the two batch > queries). Regarding the tuning of the jdbc fetch size I can only define a > single value as query hint as far as I can gather. I take it that it will > only taking effect for the A-query wouldn't it? How may I effect then the > fetch
size for the batch queries. Or, I'm totally wrong here? > > --- On Thu, 10/2/08, James Sutherland <jamesssss@xxxxxxxxx> wrote: > From: James Sutherland <jamesssss@xxxxxxxxx> > Subject: Re: [eclipselink-users] batch reading with separate fetch size > setting > To: eclipselink-users@xxxxxxxxxxx > Date: Thursday, October 2, 2008, 6:57 AM > > I'm not exactly sure I understand what you mean perhaps give an example. > > Assuming you want to set the fetch size of the nested batch queries, there > is no easy way to do this. However you could prepare() your query, then > access the getBatchReadMappingQueries() that are generated to customize > any > of the nested batch queries. > > > > Kate Lain wrote: >> >> Hi, >> >> >> >> for performance reasons I've optimized my
queries using batch reading >> and fetch size tuning - but is there a way to set the fetch size separate >> per >> batch query? >> >> Thomas >> >
----- --- http://wiki.eclipse.org/User:James.sutherland.oracle.com James Sutherland http://www.eclipse.org/eclipselink/ EclipseLink , http://www.oracle.com/technology/products/ias/toplink/ TopLink Wiki: http://wiki.eclipse.org/EclipseLink EclipseLink , http://wiki.oracle.com/page/TopLink TopLink Forums: http://forums.oracle.com/forums/forum.jspa?forumID=48 TopLink , http://www.nabble.com/EclipseLink-f26430.html EclipseLink Book: http://en.wikibooks.org/wiki/Java_Persistence Java Persistence -- View this message in context: http://www.nabble.com/batch-reading-with-separate-fetch-size-setting-tp19767497p19839612.html Sent from the EclipseLink - Users mailing list archive at
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