> But it would really help us a lot if we could get this to > work, so maybe I can find the time later.
Yeah, would be cool if you get a chance to try it out with a HEAD build of either master or 3.1, and see which problems still remain. Thanks for the information you shared so far. Andrus On Aug 6, 2014, at 12:35 PM, Erlend Birkenes <e...@dataloy.com> wrote: > Ok, I'll Jira it when I have a moment. > > But I also just discovered that all the flattened attributes are null in > the resolved objects (and in the DataRow), even though the data is present > in the query result. > > I was hoping there would be a quick fix to let me use joint prefetch, but > this, together with the problem with combining joint and disjoint_by_id, > makes me think that joint prefetch has more problems than I thought. I'll > go back to using only disjoint_by_id and not dig any deeper into this, at > least for now. But it would really help us a lot if we could get this to > work, so maybe I can find the time later. > > – > Erlend <http://www.dataloy-systems.com> > > > 2014-08-06 8:40 GMT+02:00 Andrus Adamchik <and...@objectstyle.org>: > >> Actually, checking the release notes [1], we have a bunch of >> prefetch-related fixes in (yet unreleased) 3.2M2 - CAY-1928, CAY-1695, >> CAY-1905. 1905 and 1928 are also fixed on 3.1 branch >> >> Could you maybe try your case with a source code build of Cayenne (either >> 3.1 or master) ? >> >> Thanks, >> Andrus >> >> [1] >> https://github.com/apache/cayenne/blob/master/docs/doc/src/main/resources/RELEASE-NOTES.txt >> [2] >> https://github.com/apache/cayenne/blob/STABLE-3.1/docs/doc/src/main/resources/RELEASE-NOTES.txt >> >> On Aug 6, 2014, at 9:34 AM, Andrus Adamchik <and...@objectstyle.org> >> wrote: >> >>>> This is clearly a bug. Should I create a JIRA issue? >>> >>> Hi Erlend, >>> >>> Yes, please Jira it. Sounds like a bug. >>> >>> Thanks, >>> Andrus >>> >>> >>> On Aug 5, 2014, at 2:07 PM, Erlend Birkenes <e...@dataloy.com> wrote: >>> >>>> Hi >>>> >>>> I discovered a problem with joint prefetch and flattened attributes. >> This >>>> is in 3.1B2 which is the version we use at the moment. Not sure if this >> is >>>> the lates or not.. >>>> >>>> If I have a entity A with a normal relationship to an entity B, and B >> has >>>> flattened attributes from C via toCdbrel.SOME_PROPERTY. >>>> This works fine normally. But when using joint prefetch the table >> aliases >>>> in the query will be wrong. (Querying A and prefetching B). >>>> If there are multiple flattened attributes, C will also be joined in >>>> multiple times. >>>> >>>> The problem is in SelectTranslator#appendQueryColumns. >>>> This section adds columns from the target entity of a joint prefetch, >>>> including relationships for flattened attributes: >>>> >>>> while (targetObjAttrs.hasNext()) { >>>> ObjAttribute oa = targetObjAttrs.next(); >>>> Iterator<CayenneMapEntry> dbPathIterator = oa.getDbPathIterator(); >>>> while (dbPathIterator.hasNext()) { >>>> Object pathPart = dbPathIterator.next(); >>>> >>>> if (pathPart == null) { >>>> throw new CayenneRuntimeException( >>>> "ObjAttribute has no component: " >> + >>>> oa.getName()); >>>> } >>>> else if (pathPart instanceof DbRelationship) { >>>> DbRelationship rel = (DbRelationship) pathPart; >>>> dbRelationshipAdded(rel, JoinType.INNER, null); >>>> //PROBLEM >>>> } >>>> else if (pathPart instanceof DbAttribute) { >>>> DbAttribute attribute = (DbAttribute) pathPart; >>>> >>>> appendColumn(columns, oa, attribute, attributes, >>>> labelPrefix >>>> + '.' >>>> + attribute.getName()); >>>> } >>>> } >>>> } >>>> >>>> The problem is that dbRelationshipAdded sets the topNode of the >> JoinStack >>>> to the new node when a relationship is added and this is never reset in >>>> this case. So every time a relationship is added in this loop it will >> add a >>>> node to the previously added node. This will increase the tableAlias by >> 1 >>>> for every relationship, and also cause any attributes directly on B to >>>> belong to the wrong node and therefore get the wrong tableAlias. It will >>>> also cause an additional join, but joined to the wrong table. >>>> >>>> The topNode of the JoinStack needs to be reset to the correct value >> after >>>> handing each attribute, or more presisely: after the "while >>>> (dbPathIterator.hasNext())" loop the topNode needs to be the same as it >> was >>>> before the loop, because we are still processing attributes on the same >>>> entity (B in this case). >>>> >>>> Storing the current topNode, and resetting it after processing each >>>> attribute fixed the problem for me. Like this: >>>> >>>> while (targetObjAttrs.hasNext()) { >>>> JoinTreeNode topNode = getJoinStack().topNode; // FIX >>>> ObjAttribute oa = targetObjAttrs.next(); >>>> Iterator<CayenneMapEntry> dbPathIterator = >>>> oa.getDbPathIterator(); >>>> while (dbPathIterator.hasNext()) { >>>> Object pathPart = dbPathIterator.next(); >>>> >>>> if (pathPart == null) { >>>> throw new CayenneRuntimeException( >>>> "ObjAttribute has no component: " + >>>> oa.getName()); >>>> } >>>> else if (pathPart instanceof DbRelationship) { >>>> DbRelationship rel = (DbRelationship) >> pathPart; >>>> dbRelationshipAdded(rel, JoinType.INNER, >> null); >>>> } >>>> else if (pathPart instanceof DbAttribute) { >>>> DbAttribute attribute = (DbAttribute) >> pathPart; >>>> >>>> appendColumn(columns, oa, attribute, >>>> attributes, labelPrefix >>>> + '.' >>>> + attribute.getName()); >>>> } >>>> } >>>> getJoinStack().topNode = topNode; // FIX >>>> } >>>> >>>> resetJoinStack() can't be used in this case, since we don't want the >>>> rootNode. >>>> >>>> I've run the Cayenne tests after this change with no errors, but I've >> only >>>> done limited testing in our own app so far. >>>> >>>> This is clearly a bug. Should I create a JIRA issue? >>>> >>>> >>>> – >>>> Erlend <http://www.dataloy-systems.com> >>> >>> >> >>
