If you create a secondary index in Phoenix on the table on single or selected columns, that index (which will be added to Hbase) will be used to return data. For example in below MARKETDATAHBASE_IDX1 is an index on table MARKETDATAHBASE and is used by the query
0: jdbc:phoenix:rhes564:2181> EXPLAIN select count(1) from MARKETDATAHBASE; +--------------------------------------------------------------------+ | PLAN | +--------------------------------------------------------------------+ | CLIENT 1-CHUNK PARALLEL 1-WAY FULL SCAN OVER MARKETDATAHBASE_IDX1 | | * SERVER FILTER BY FIRST KEY ONLY* | | SERVER AGGREGATE INTO SINGLE ROW | +--------------------------------------------------------------------+ HTH Dr Mich Talebzadeh LinkedIn * https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw <https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUrV8Pw>* http://talebzadehmich.wordpress.com *Disclaimer:* Use it at your own risk. Any and all responsibility for any loss, damage or destruction of data or any other property which may arise from relying on this email's technical content is explicitly disclaimed. The author will in no case be liable for any monetary damages arising from such loss, damage or destruction. On 30 October 2016 at 11:42, Fawaz Enaya <m.fawaz.en...@gmail.com> wrote: > Hi All in this great project, > > > I have an HBase cluster of four nodes, I use Phoenix to access HBase, but > I do not know why its too much slow to execute SELECT count(*) for table > contains 5 million records it takes 8 seconds. > Below is the explain for may select statement > > CLIENT 6-CHUNK 9531695 ROWS 629145639 BYTES PARALLEL 1-WAY FULL SCAN OVER > TABLE* |* > > *| * SERVER FILTER BY FIRST KEY ONLY > * |* > > *| * SERVER AGGREGATE INTO SINGLE ROW > Anyone can help. > > Many Thanks > -- > Thanks & regards, > >
