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From "T Jake Luciani (JIRA)" <>
Subject [jira] Commented: (CASSANDRA-1472) Add bitmap secondary indexes
Date Mon, 10 Jan 2011 20:40:46 GMT


T Jake Luciani commented on CASSANDRA-1472:

Overall, this is a really great refactoring of the secondary index stuff!

After reviewing CASSANDRA-1916 I was disappointed with the secondary index code, this makes
me much happier!

Notes on the work so far:
  - I renamed KEYS_BITMAP to just BITMAP,  fixed some spots that could leak files, and fixed
a compaction bug related to 1916 with testcase.
  - There are some changes in here that seem to be bug fixes for other issues, specifically
the changes to, this should probably go into it's own ticket?
  - I see in SSTableWriter that BMT will fail on secondary indexed CFs now.  Why fail though?
Can't they just be built on restart?
  - The whole BitmapIndexWriter Scratch space has me slightly concerned.  I think writing
lots of segment files to disk then merging them to one seems, well like more compaction. I
guess it's the downside of not using SSTables like keys does.
  - AVRO, I don't see the value here. The structures are so simple any you bypass it for bitset's
anyway.   The value of using our BRAF is you have all the work to avoid polluting the page
cache done so this code doesn't affect live reads.  As it stands this is going to go against
all that work. I think you should serialize this natively. 
  - I mentioned above that on the fly indexes should be allowed, however this can happen in
a subsequent ticket if you prefer.
  - As Nick mentioned it would be nice to have some stats on the index available in JMX, for
a subsequent ticket.
  - I think this implementation should probably be the only secondary index format we support
(What's the value of keeping KEYS over this?) We can remove KEYS after.
  But this is really nicely thought out, good stuff!

> Add bitmap secondary indexes
> ----------------------------
>                 Key: CASSANDRA-1472
>                 URL:
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Stu Hood
>            Assignee: Stu Hood
>             Fix For: 0.7.1
>         Attachments: 0.7-1472-v5.tgz, 1472-v3.tgz, 1472-v4.tgz, 1472-v5.tgz, anatomy.png,
> 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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