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https://issues.apache.org/jira/browse/CASSANDRA-1472?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12980568#action_12980568
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Stu Hood commented on CASSANDRA-1472:
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>> I think this implementation should probably be the only secondary index
>> format we support (What's the value of keeping KEYS over this?)
> Agreed, pending the optimizations mentioned in previous comments.
I need to retract this statement: I don't think we should remove the KEYS
index, for a few reasons:
# The false positives generated by these bitmap indexes have worst case
behaviour with rapidly changing data: if a row matches the index in _any
sstable_, we have to read all sstables that contain the row in order to resolve
the data and determine whether it _actually_ matches. On the other hand, they
will be damn near optimal when you are doing a smaller fraction of updates
# The reason the implementation is called KEYS is that it is a traditional
index, containing only a pointer to the base data (a key). They are only 1 step
away from being fully materialized views, which has a lot of potential for the
entity groups that Ellis is interested in
# KEYS indexes will gain _very_ nice benefits from the compression introduced
by CASSANDRA-674 (since they contain value-sorted data)
> Add bitmap secondary indexes
> ----------------------------
>
> Key: CASSANDRA-1472
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1472
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Stu Hood
> Assignee: Stu Hood
> Fix For: 0.7.1
>
> Attachments: 0.7-1472-v5.tgz, 0.7-1472-v6.tgz,
> 0019-Rename-bugfixes-and-fileclose.txt, 1472-v3.tgz, 1472-v4.tgz,
> 1472-v5.tgz, anatomy.png, v4-bench-c32.txt
>
>
> Bitmap indexes are a very efficient structure for dealing with immutable
> data. We can take advantage of the fact that SSTables are immutable by
> attaching them directly to SSTables as a new component (supported by
> CASSANDRA-1471).
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