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Date: Tue, 6 Jan 2015 09:26:34 +0000 (UTC)
From: "Benedict (JIRA)" <jira@apache.org>
To: commits@cassandra.apache.org
Message-ID: <JIRA.12764113.1419905045000.17911.1420536394938@Atlassian.JIRA>
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Subject: [jira] [Commented] (CASSANDRA-8547) Make
 RangeTombstone.Tracker.isDeleted() faster
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    [ https://issues.apache.org/jira/browse/CASSANDRA-8547?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14265891#comment-14265891 ] 

Benedict commented on CASSANDRA-8547:
-------------------------------------

This looks like something [~slebresne] should take a look at.

> Make RangeTombstone.Tracker.isDeleted() faster
> ----------------------------------------------
>
>                 Key: CASSANDRA-8547
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8547
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>         Environment: 2.0.11
>            Reporter: Dominic Letz
>            Assignee: Dominic Letz
>             Fix For: 2.1.3
>
>         Attachments: Selection_044.png, cassandra-2.0.11-8547.txt, cassandra-2.1-8547.txt, rangetombstone.tracker.txt
>
>
> During compaction and repairs with many tombstones an exorbitant amount of time is spend in RangeTombstone.Tracker.isDeleted().
> The amount of time spend there can be so big that compactions and repairs look "stalled" and the time remaining time estimated frozen at the same value for days.
> Using visualvm I've been sample profiling the code during execution and both in Compaction as well as during repairs found this. (point in time backtraces attached)
> Looking at the code the problem is obviously the linear scanning:
> {code}
>         public boolean isDeleted(Column column)
>         {
>             for (RangeTombstone tombstone : ranges)
>             {
>                 if (comparator.compare(column.name(), tombstone.min) >= 0
>                     && comparator.compare(column.name(), tombstone.max) <= 0
>                     && tombstone.maxTimestamp() >= column.timestamp())
>                 {
>                     return true;
>                 }
>             }
>             return false;
>         }
> {code}
> I would like to propose to change this and instead use a sorted list (e.g. RangeTombstoneList) here instead.


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