[jira] Issue Comment Edited: (HADOOP-2291) [hbase] Add row count estimator

["Edward Yoon (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-2291?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12553598 ] 

udanax edited comment on HADOOP-2291 at 12/19/07 11:33 PM:
----------------------------------------------------------------

||real count||estimated count||
|676|784|
|17576|21058|
|456976|501647|
|7580124|8120647|
|65201750|82648211|

(row count of sample space * sample size) was used for calculate.
Test result is just fine, but Let me see about it.

If you have a good idea, please let me know.


      was (Author: udanax):
    ||real count||estimated count||
|676|784|
|17576|21058|
|456976|501647|
|7580124|8120647|
|65201750|8264821|

(row count of sample space * sample size) was used for calculate.
Test result is just fine, but Let me see about it.

If you have a good idea, please let me know.

  
> [hbase] Add row count estimator
> -------------------------------
>
>                 Key: HADOOP-2291
>                 URL: https://issues.apache.org/jira/browse/HADOOP-2291
>             Project: Hadoop
>          Issue Type: New Feature
>          Components: contrib/hbase
>            Reporter: stack
>            Assignee: Edward Yoon
>            Priority: Minor
>         Attachments: 2291_v01.patch, Keying.java
>
>
> Internally we have a little tool that will do a rough estimate of how many rows there are in a dataHbase.  It keeps getting larger and larger partitions running scanners until it turns up > N occupied rows.  Once it has a number > N, it multiples by the partition size to get an approximate row count.  
> This issue is about generalizing this feature so it could sit in the general hbase install.  It would look something like:
> {code}
> long getApproximateRowCount(final Text startRow, final Text endRow, final long minimumCountPerPartition, final long maximumPartitionSize)
> {code}
> Larger minimumCountPerPartition and maximumPartitionSize values would make the count more accurate but would mean the method ran longer.

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