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From "Stefania (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7392) Abort in-progress queries that time out
Date Fri, 03 Jul 2015 07:28:05 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7392?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14612937#comment-14612937
] 

Stefania commented on CASSANDRA-7392:
-------------------------------------

[~slebresne], I would like to know how to best abort a read operation. I think we have several
options:

- Add an "abort requested" control field (OpState) in the code [here|https://github.com/stef1927/cassandra/commits/7392]
to ReadCommand but this means changing the constructor chain which is very complex (the index
read command needs to inherit the control field of the main command - unless we make it not
final)
- Pass it as an argument to the various methods (executeLocally, queryStorage, search, etc)
- Add it to ReadOrderGroup, which is passed almost everywhere but it isn't really related
- Simply stop the iterator in executeLocally with a wrapper iterator (this is required anyway
I believe but it would not abort the index reads) 

Could you comment on :
- your preferred option, I don't want to spoil your design :)
- whether the code is stable or whether there is some refactoring still missing that I should
wait for or help out with

> Abort in-progress queries that time out
> ---------------------------------------
>
>                 Key: CASSANDRA-7392
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7392
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>            Reporter: Jonathan Ellis
>            Assignee: Stefania
>             Fix For: 3.x
>
>
> Currently we drop queries that time out before we get to them (because node is overloaded)
but not queries that time out while being processed.  (Particularly common for index queries
on data that shouldn't be indexed.)  Adding the latter and logging when we have to interrupt
one gets us a poor man's "slow query log" for free.



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