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https://issues.apache.org/jira/browse/HADOOP-2291?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12553744
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stack commented on HADOOP-2291:
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What is state of this issue Edward? Will it not work on billions of rows?
Other comments on the patch are:
+ We should add a HTable.getTableDescriptor and a HTable.getColumnFamilies?
+ Comments would be helpful. For example would be good to explain why you of a
sudden set a variable 'i' equal to 2 and a comment confirming what you are
doing finding midkeys over and over again would be helpful (Won't this take a
long time on a big table)?
+ If in your search for endKey turns up a null, won't you get a NPE when you
convert back from base64?
+ Would suggest that the estimator or an estimator override take as inputs the
smallest slice to start with and the largest slice that the estimator should
try.
> [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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