CQL Join on Coherence Cache with Composite Key

Question

I have a Coherence Cache with a composite key and I want to join a channel to records in that cache with a CQL processor. When I deploy the package containing the processor, I get the following error:
+italics14:32:35,938 | alter query SimpleQuery start                                                                        | [ACTIVE] ExecuteThread: '7' for queue: 'weblogic.kernel.Default (self-tuning)' | CQLServer | FATAL+
+14:32:35,938 | alter query >>SimpleQuery<< start+
+specified predicate requires full scan of external source which is not supported. please modify the join predicate | [ACTIVE] ExecuteThread: '7' for queue: 'weblogic.kernel.Default (self-tuning)' | CQLServer | FATAL+
I think that I'm using the entire key. If I change the key to a single field, it deploys OK. I found a similar issue when I defined a Java class to represent the composite key. Is it possible to join in this way on a composite key cache?
I could define another field which is a concatenation of the fields in the composite key but this is a little messy.
My config is as below:
<wlevs:caching-system id="MyCache" provider="coherence" />
<wlevs:event-type-repository>
<wlevs:event-type type-name="SimpleEvent">
          <wlevs:properties>
               <wlevs:property name="field1" type="char" />
               <wlevs:property name="field2" type="char" />
          </wlevs:properties>
</wlevs:event-type>
</wlevs:event-type-repository>
     <wlevs:channel id="InChannel" event-type="SimpleEvent" >
          <wlevs:listener ref="SimpleProcessor" />
     </wlevs:channel>
     <wlevs:processor id="SimpleProcessor">
          <wlevs:listener ref="OutChannel" />
          <wlevs:cache-source ref="SimpleCache" />
     </wlevs:processor>
     <wlevs:channel id="OutChannel" event-type="SimpleEvent" >
     </wlevs:channel>
     <wlevs:cache id="SimpleCache" value-type="SimpleEvent"
          key-properties="field1,field2"
          caching-system="MyCache" >
     </wlevs:cache>
and the processor CQL is as follows:
<processor>
<name>SimpleProcessor</name>
<rules>
<query id="SimpleQuery">
<![CDATA[ 
            select I.field1, I.field2 from InChannel [now] as I,
SimpleCache as S where
I.field1 = S.field1 and
I.field2 = S.field2
]]> </query>
</rules>
</processor>
Thanks
Mike

Answer 1

Unfortunately, joining on composite keys in Coherence is not supported in the released versions. This will be supported in 12g release.
As you mention, defining another field as key, which is the concatenation of the original keys is the workaround.