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https://issues.apache.org/jira/browse/SPARK-15874?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Reynold Xin closed SPARK-15874.
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Resolution: Not A Problem
> HBase rowkey optimization support for Hbase-Storage-handler
> -----------------------------------------------------------
>
> Key: SPARK-15874
> URL: https://issues.apache.org/jira/browse/SPARK-15874
> Project: Spark
> Issue Type: New Feature
> Components: SQL
> Reporter: Weichen Xu
> Original Estimate: 720h
> Remaining Estimate: 720h
>
> Currently, Spark-SQL use `org.apache.hadoop.hive.hbase.HBaseStorageHandler`
> for Hbase table support, which has poor optimization. for example, query such
> as
> select * from hbase_tab1 where rowkey_col = 'abc';
> will cause full table scan(each table region turn into a scan split and do
> full region scan).
> In fact, it is easy to implement the following optimization:
> 1.
> SQL such as
> `select * from hbase_tab1 where rowkey_col = 'abc';`
> or
> `select * from hbase_tab1 where rowkey_col = 'abc' or rowkey_col = 'abd' or
> ...;`
> can use hbase rowkey `Get`/`multiGet` API to execute efficiently.
> 2.
> SQL such as
> `select * from hbase_tab1 where rowkey_col = 'abc%';`
> can use hbase rowkey `Scan` API to execute efficiently.
> Higher-level SQL optimization will benefit from such optimization, for
> example, there is a very small table(such as incremental Data) `small_tab1`,
> SQL such as
> `select * from small_tab1 join hbase_tab1 on small_tab1.key1 =
> hbase_tab1.rowkey_col`
> can use classic small-table driven join optimization:
> loop each record of small_tab1, and exact each small_tab1.key1 as
> hbase_tab1's rowkey, and use hbase Get API, the join will execute efficiently.
> The scenario described above is very common, manay business system may have
> several tables which has major-key such as userID, and they often store them
> in HBase. But, several times people have requirement to do some analysis with
> SQL, and these SQL will have good optimization if the SQL execution plan has
> a good support to HBase rowkey.
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