Re: [eclipselink-users] EclipseLink cache configuration for Struts plus

[sonavor <jw@xxxxxxxxxxxxxx>]

I decided to try the query hint first.

That appears to work.  It is a little difficult to setup the test scenario
to test the problem as I have to create some test images (at least three
entries) so I ran two test scenarios - two tests with three new media
entries for each scenario.  In both tests the page populated by the query I
have had the problem with worked after using the query hint -
q.setHint("eclipselink.refresh", "true");

So that is great!

The thumbnail attribute is just a file name String.  It isn't a transient
property but an actual database column.  There are probably some other
attributes that are (were) not refreshing but the thumbnail attribute is the
one that is noticeable on the resulting web page.

Thanks for the solution.  I really appreciate it.

-sonavor


James Sutherland wrote:
> 
> Is it just the thumbnail that is null, or other mapped attributes?  Are
> you mapping the thumbnail to the database, or not storing it in the
> database?  If it is transient, then how do you expect it to come back when
> reading from the database?
> 
> Otherwise, it may have something to do with the first/maxResults, try
> removing this to confirm if this is causing the issue.  Also you can set
> the query to refresh using the query hint, "eclipselink.refresh"="true".
> 
> 
> 
> sonavor wrote:
>> 
>> It is odd.
>> I turned more logging on but there is too much information to put in
>> here.
>> 
>> Here is some more information about what is going on.  I use and web
>> application admin screen to add new media definition records to a MySql
>> table.  A new media definition includes several child, media item,
>> records.  Two of those child, media item records represent a thumbnail
>> image and a preview image.  In my latest test I added three new media
>> definitions.  Those records go into the database as usual without a
>> hitch.  For each of those three definitions I placed the necessary image
>> (JPG) files where the web app can find them.  Now here is where the odd
>> behavior occurs.  After those inserts I run a query from my web
>> application search screen that finds the new records.  Of those three
>> inserted media definition records, the first one does not return the
>> thumbnail.  If I drill into the media definition where the application
>> performs an EntityManager find(MediaListing.class, mediaId) then the
>> thumbnail appears...and from then on, appears on a search.  When I say
>> "drill into" - what I mean is that the search finds the media definition
>> record but it does not seem to have all of the necessary information such
>> as the filename of the thumbnail image.  It isn't able to retrieve that
>> child attribute.
>> 
>> To double check I ran another test where I entered three new media
>> definitions.  Same thing happens - the first record I entered cannot find
>> the thumbnail on the search until I drill into the record.  
>> 
>> The JPA query I am running is this -
>>             Integer subjectId =
>> searchDto.getMediaSubject().getSubjectId();
>>             StringBuffer qSB = new StringBuffer();
>>             qSB.append("SELECT object(m) FROM MediaListing as m JOIN
>> m.mediaSubject s WHERE s.subjectId = :argSubjectId");
>>             Query q = em.createQuery(qSB.toString());
>>             q.setParameter("argSubjectId", subjectId);
>>             q.setFirstResult(startRow);
>>             q.setMaxResults(rowCount);
>>             List<MediaListing> mList = q.getResultList();
>>             if (mList != null) {
>>                 log("findMediaSearchByPaged...found " + mList.size() +
>> "MediaListing records ...");
>>                 for (Iterator i = mList.iterator(); i.hasNext();) {
>>                     MediaListing ml = (MediaListing) i.next();
>>                     ml.getMediaType();
>>                     ml.getMediaRepositoryItemCollection();
>>                 }
>>             }
>> 
>> I added the ml.getMediaType() and ml.getMediaRepositoryItemCollection()
>> lines to force the entity manager to retrieve the MediaListing (ml)
>> record child records because of the lazy fetch.  I know I can set the
>> fetch strategy with an annotation but I put those lines in there just to
>> see if it would force the child attributes to be received.  In this case
>> it doesn't seem to help.
>> 
>> The EclipseLink output for the query where I retrieve the media items is
>> like this (I run a count first because I paginate the searches) -
>> [EL Fine]: 2009-09-29
>> 10:52:02.109--ServerSession(4729773)--Connection(14151320)--Thread(Thread[TP-Processor3,5,main])--SELECT
>> COUNT(t0.MEDIA_ID) FROM MEDIA_LISTING t0, MEDIA_SUBJECT t1 WHERE
>> ((t1.SUBJECT_ID = ?) AND (t1.SUBJECT_ID = t0.MEDIA_SUBJECT_ID))
>>         bind => [518]
>> 
>> followed by -
>> 
>> [EL Fine]: 2009-09-29
>> 10:52:02.202--ServerSession(4729773)--Connection(26375417)--Thread(Thread[TP-Processor3,5,main])--SELECT
>> t1.MEDIA_ID AS MEDIA_ID1, t1.LAST_UPDATE AS LAST_UPDATE2, t1.MEDIA_CODE
>> AS MEDIA_CODE3, t1.MEDIA_TITLE AS MEDIA_TITLE6, t1.MEDIA_DESCRIPTION AS
>> MEDIA_DESCRIPTION7, t1.MEDIA_TYPE_ID AS MEDIA_TYPE_ID11, t1.AUTHOR_ID AS
>> AUTHOR_ID12, t1.MEDIA_SUBJECT_ID AS MEDIA_SUBJECT_ID13,
>> t1.MEDIA_CATEGORY_ID AS MEDIA_CATEGORY_ID14, t1.MEDIA_FORMAT_ID AS
>> MEDIA_FORMAT_ID15 FROM MEDIA_SUBJECT t0, MEDIA_LISTING t1 WHERE
>> ((t0.SUBJECT_ID = ?) AND (t0.SUBJECT_ID = t1.MEDIA_SUBJECT_ID)) LIMIT ?,
>> ?
>>         bind => [518, 0, 16]
>> 
>> I have added logic to my web page build for the search results to detect
>> any null attribute values for the returned MediaListing objects and that
>> is preventing any page blow-ups.  In this case where one of the media
>> records is not able to retrieve the thumbnail file image I detect that
>> and substitute an "image not found" JPG.  
>> 
>> I can't use the refreshIdentityMapResult() method on the query I am
>> running now because it is just a basic Query type object, not a
>> ReadAllQuery. 
>> 
>> -sonavor
>> 
>> 
>> 
> 
> 

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