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Posted to commits@cassandra.apache.org by "Aleksey Yeschenko (JIRA)" <ji...@apache.org> on 2016/03/18 21:55:33 UTC
[jira] [Resolved] (CASSANDRA-6048) Add the ability to use multiple
indexes in a single query
[ https://issues.apache.org/jira/browse/CASSANDRA-6048?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Aleksey Yeschenko resolved CASSANDRA-6048.
------------------------------------------
Resolution: Duplicate
Assignee: (was: Alex Liu)
Reviewer: (was: Sylvain Lebresne)
Fix Version/s: (was: 3.x)
This is planned for SASI in CASSANDRA-10765, and isn't going to happen for the old implementation.
> Add the ability to use multiple indexes in a single query
> ---------------------------------------------------------
>
> Key: CASSANDRA-6048
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6048
> Project: Cassandra
> Issue Type: New Feature
> Reporter: Alex Liu
> Attachments: 6048-1.2-branch.txt, 6048-trunk.txt
>
>
> Existing data filtering uses the following algorithm
> {code}
> 1. find best selective predicate based on the smallest mean columns count
> 2. fetch rows for the best selective predicate predicate, then filter the data based on other predicates left.
> {code}
> So potentially we could improve the performance by
> {code}
> 1. joining multiple predicates then do the data filtering for other predicates.
> 2. fine tune the best predicate selection algorithm
> {code}
> For multiple predicate join, it could improve performance if one predicate has many entries and another predicate has a very few of entries. It means a few index CF read, join the row keys, fetch rows then filter other predicates
> Another approach is to have index on multiple columns.
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