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https://issues.apache.org/jira/browse/HBASE-32?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12565617#action_12565617
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Bryan Duxbury commented on HBASE-32:
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I was thinking, that rather than sampling and resampling repeatedly, maybe what
you could do is look at the region start keys, figure out what the edit
distance between start and end keys is as a proxy for size of the region, and
then scan the presumed largest and presumed smallest regions. This would give
you a lower and upper bound on your table size. If your selections of smallest
and largest regions happened to be bad, ie the counts were inverted, you can
always just flip them.
> [hbase] Add row count estimator
> -------------------------------
>
> Key: HBASE-32
> URL: https://issues.apache.org/jira/browse/HBASE-32
> Project: Hadoop HBase
> Issue Type: New Feature
> Components: client
> Reporter: stack
> 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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