[jira] [Commented] (CASSANDRA-12107) Fix range scans for table with live static rows

["Benjamin Lerer (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-12107?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15354879#comment-15354879 ] 

Benjamin Lerer commented on CASSANDRA-12107:
--------------------------------------------

[~sharvanath], could you provide the table schema and the rows with uuid: 6b470c3e43ee06d1, 484b091ca97803cd, c348aaec2f1e4b85 or a simple unit test to help us reproduce the problem.
Your patch might be valid but it is difficult to say without a way to reproduce the problem.

> Fix range scans for table with 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
>              Labels: patch-available
>             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 for trunk (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. However, since trunk has some failures already, 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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