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https://issues.apache.org/jira/browse/CASSANDRA-1600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12988732#comment-12988732
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Ben Pirt edited comment on CASSANDRA-1600 at 1/31/11 11:47 AM:
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Hopefully it is useful to get another use case for why this is important to a
real-world user.
We are storing time-series data and would like to be able to pull out all
values between time A and time B that have a specific value as a property.
Because we aren't able to combine a range slice with an indexed slice we are
having to duplicate our data into several keyspaces so we can still do the
range slice. Our ideal scenario would be to be able to say "Give me all keys
between time A and time B whose property P is greater than or equal to 5"
I would imagine that in another time-series type scenario of storing lots of
logs (e.g. Apache logs) it would be very useful to say "Give me all logs
between time A and time B with a status code of 200"
My only question is how this works in conjunction with limit. As a user I would
expect that if I limited the results to 100, I would get a max of 100 results
between time A and time B which matched the secondary index query, however I
understand this may be at odds with how get_range applies the limit. I would
want the limit to be applied after the secondary index predicate has been
applied.
Please do let me know if I'm misunderstanding things and that there is a better
way of doing this, but it seems to me that it would be very useful
functionality. Very much looking forward to 0.8 for this fix alone!
was (Author: bjpirt):
Hopefully it is useful to get another use case for why this is important to
a real-world user.
We are storing time-series data and would like to be able to pull out all
values between time A and time B that have a specific value as a property.
Because we aren't able to combine a range slice with an indexed slice we are
having to duplicate our data into several keyspaces so we can still do the
range slice. Our ideal scenario would be to be able to say "Give me all keys
between time A and time B whose property P is greater than or equal to 5"
I would imagine that in another time-series type scenario of storing lots of
logs (e.g. Apache logs) it would be very useful to say "Give me all logs
between time A and time B with a status code of 200"
Please do let me know if I'm misunderstanding things and that there is a better
way of doing this, but it seems to me that it would be very useful
functionality. Very much looking forward to 0.8 for this fix alone!
> Merge get_indexed_slices with get_range_slices
> ----------------------------------------------
>
> Key: CASSANDRA-1600
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1600
> Project: Cassandra
> Issue Type: Improvement
> Components: API
> Affects Versions: 0.7 beta 1
> Reporter: Stu Hood
> Fix For: 0.8
>
> Attachments:
> 0001-Add-optional-IndexClause-to-KeyRange-and-serialize-wit.txt,
> 0002-Drop-the-IndexClause.count-parameter.txt,
> 0003-Execute-RangeSliceCommands-using-scan-when-an-IndexCla.txt,
> 0004-Remove-get_indexed_slices-method.txt,
> 0005-Update-system-tests-to-use-get_range_slices.txt,
> 0006-Remove-start_key-from-IndexClause-for-the-start_key-in.txt,
> 0007-Respect-end_key-for-filtered-queries.txt,
> 0008-allow-applying-row-filtering-to-sequential-scan.txt,
> 0009-rename-Index-Filter.txt, AbstractScanIterator.java
>
>
> From a comment on 1157:
> {quote}
> IndexClause only has a start key for get_indexed_slices, but it would seem
> that the reasoning behind using 'KeyRange' for get_range_slices applies there
> as well, since if you know the range you care about in the primary index, you
> don't want to continue scanning until you exhaust 'count' (or the cluster).
> Since it would appear that get_indexed_slices would benefit from a KeyRange,
> why not smash get_(range|indexed)_slices together, and make IndexClause an
> optional field on KeyRange?
> {quote}
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