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https://issues.apache.org/jira/browse/CASSANDRA-1472?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13003216#comment-13003216
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Stu Hood edited comment on CASSANDRA-1472 at 3/6/11 10:18 PM:
--------------------------------------------------------------

tjake: Yea: opening a separate ticket to discuss a generic file format makes 
sense.
----
I had a realization about this implementation of secondary indexes: I was 
originally thinking we'd be able to push all boolean queries down to the 
indexes on a per-sstable basis, but this is unfortunately not the case. We will 
not be able to push 'AND' on separate indexes down to the sstables themselves: 
we'd need to join the index from all sstables, since a row might contain one 
clause in one sstable, and another clause in another sstable. EDIT: This is 
roughly equivalent to what we'd need to do with a KEYS index (seek-wise), 
meaning that the advantage is mostly in space utilization and lack of locks.

      was (Author: stuhood):
    tjake: Yea: opening a separate ticket to discuss a generic file format 
makes sense.
----
I had a realization about this implementation of secondary indexes: I was 
originally thinking we'd be able to push all boolean queries down to the 
indexes on a per-sstable basis, but this is unfortunately not the case. We will 
not be able to push 'AND' on separate indexes down to the sstables themselves: 
we'd need to join the index from all sstables, since a row might contain one 
clause in one sstable, and another clause in another sstable.
  
> 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: 0.7.4
>
>         Attachments: 0.7-1472-v5.tgz, 0.7-1472-v6.tgz, 
> 0001-CASSANDRA-1472-rebased-to-0.7-branch.txt, 
> 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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