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From "Sharvanath Pathak (JIRA)" <j...@apache.org>
Subject [jira] [Created] (CASSANDRA-12107) Fix range scans for table live static rows
Date Wed, 29 Jun 2016 00:37:10 GMT
Sharvanath Pathak created CASSANDRA-12107:
---------------------------------------------

             Summary: Fix range scans for table live static rows
                 Key: CASSANDRA-12107
                 URL: https://issues.apache.org/jira/browse/CASSANDRA-12107
             Project: Cassandra
          Issue Type: Bug
          Components: Core
            Reporter: Sharvanath Pathak
             Fix For: 3.0.8


We were seeing some weird behaviour with limit based scan queries. In particular, we see the
following:
{noformat}
$ cqlsh -k sd -e "consistency local_quorum; SELECT uuid, token(uuid) FROM files WHERE token(uuid)
>= token('6b470c3e43ee06d1') limit 2"
Consistency level set to LOCAL_QUORUM.

 uuid             | system.token(uuid)
------------------+----------------------
 6b470c3e43ee06d1 | -9218823070349964862
 484b091ca97803cd | -8954822859271125729

(2 rows)
$ cqlsh -k sd -e "consistency local_quorum; SELECT uuid, token(uuid) FROM files WHERE token(uuid)
> token('6b470c3e43ee06d1') limit 1"
Consistency level set to LOCAL_QUORUM.

 uuid             | system.token(uuid)
------------------+----------------------
 c348aaec2f1e4b85 | -9218781105444826588
{noformat}
In the table uuid is partition key, and it has a clustering key as well.
So the uuid "c348aaec2f1e4b85" should be the second one in the limit query. After some investigation,
it seems to me like the issue is in the way DataLimits handles static rows. Here is a patch
(https://github.com/sharvanath/cassandra/commit/9a460d40e55bd7e3604d987ed4df5c8c2e03ffdc)
which seems to fix it for me. Please take a look, seems like a pretty critical issue to me.

I have forked the dtests for it as well, but since trunk has some failure I'm not fully sure
how to infer the results.
http://cassci.datastax.com/view/Dev/view/sharvanath/job/sharvanath-fixScan-dtest/
http://cassci.datastax.com/view/Dev/view/sharvanath/job/sharvanath-fixScan-testall/



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