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From Ravikumar Govindarajan <ravikumar.govindara...@gmail.com>
Subject Digest Query Seems to be corrupt on certain cases
Date Wed, 27 Mar 2013 15:15:29 GMT
We started receiving OOMs in our cassandra grid and took a heap dump. We
are running version 1.0.7 with LOCAL_QUORUM from both reads/writes.

After some analysis, we kind of identified the problem, with
SliceByNamesReadCommand, involving a single Super-Column. This seems to be
happening only in digest query and not during actual reads.

I am pasting the serialized byte array of SliceByNamesReadCommand, which
seems to be corrupt on issuing certain digest queries.

//Type is SliceByNamesReadCommand
body[0] = (byte)1;
 //This is a digest query here.
body[1] = (byte)1;

                //Table-Name from 2-8 bytes

                //Key-Name from 9-18 bytes

                //QueryPath deserialization here

                     //CF-Name from 19-30 bytes

                    //Super-Col-Name from 31st byte onwards, but gets
corrupt as found in heap dump

                    //body[32-37] = 0, body[38] = 1, body[39] = 0.  This
causes the SliceByNamesDeserializer to mark both ColName=NULL and
SuperColName=NULL, fetching entire wide-row!!!

                   //Actual super-col-name starts only from byte 40,
whereas it should have started from 31st byte itself

Has someone already encountered such an issue? Why is the super-col-name
not correctly de-serialized during digest query.

--
Ravi

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