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https://issues.apache.org/jira/browse/CASSANDRA-226?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12721630#action_12721630
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Chris Goffinet commented on CASSANDRA-226:
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If we do this, i think we should at least provide a time sorted comparator by 
default for users who want this. We (Digg) certainly have a need for time 
ordering.

> Make time-sorted CFs behave consistently
> ----------------------------------------
>
>                 Key: CASSANDRA-226
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-226
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Jonathan Ellis
>             Fix For: 0.4
>
>
> Time-sorted CFs are indexed and sorted by time in the SSTable.  So lookup by 
> name is inefficient, and compaction sucks (i.e., we can run out of memory), 
> because we combine by name even though we sort by time. (see CASSANDRA-16)
> The right fix is, for time-sorted columns we need to recognize that the right 
> "key" as it were is (time, name) not name.  We should allow slice by time and 
> lookup by time or time,name but not just name.  (Similarly, we should not 
> allow lookup by time on name-sorted CFs.)  This means that name will not 
> necessarily be unique in time-sorted CFs but that is the right behavior!  
> Time-based CFs are more like appending to a list than putting to a map.
> (As part of this we could track the most recent append in time-sorted CFs to 
> prevent the bug in CASSANDRA-223.  I am not sure that is the "right" way to 
> go but I do mention it as a possibility that this change enables.)
> In the code, this will allow more regular treatment of CFs and less special 
> casing.  (It will also allow using only a single map for memtable columns, 
> reducing memory usage -- see CASSANDRA-51.)
> Implementation notes: we may be able to represent both types of CF with a 
> pluggable Comparator + Indexer combination, which would solve CASSANDRA-185 
> and CASSANDRA-189 at the same time.

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