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From "HBase Review Board (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HBASE-3162) Add TimeRange support into Increment to optimize for counters that are partitioned on time
Date Sun, 31 Oct 2010 20:34:25 GMT

    [ https://issues.apache.org/jira/browse/HBASE-3162?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12926776#action_12926776
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HBase Review Board commented on HBASE-3162:
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Message from: thekhemani@facebook.com

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The timestamp that we put in the column-qualifier to create hourly counters need not be in
sync with the KV timestamp. This is because there are times when the log stream falls behind
and we might be updating couple of hours old counters. The time-range that we provide has
to be dynamically determined based on the current log-stream delay.


This will really work well if along with hourly counters we also have hourly store files.
If everything gets compacted into a single store file then this change doesn't help much.


- khemani





> Add TimeRange support into Increment to optimize for counters that are partitioned on
time
> ------------------------------------------------------------------------------------------
>
>                 Key: HBASE-3162
>                 URL: https://issues.apache.org/jira/browse/HBASE-3162
>             Project: HBase
>          Issue Type: Improvement
>          Components: client, regionserver
>    Affects Versions: 0.90.0
>            Reporter: Jonathan Gray
>            Assignee: Jonathan Gray
>            Priority: Minor
>             Fix For: 0.90.0
>
>         Attachments: HBASE-3162-v1.patch
>
>
> In many use cases of increments, a given counter is only incremented during a specific
window of time (ie. the counters are partitioned/sharded by time).
> With this kind of schema, you are constantly creating new counters.  When a new counter
is "created" (incremented the first time) you will always end up looking at a block from every
file in the region because no previous value will exist.  However, with the new TimeRange
optimizations that skip files if they don't contain values of the TimeRange you're interested
in, we could utilize that information to optimize the Get within the increment.
> This would be optional and an addition to the Increment class.

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