Ok we hope that partitioning improves performance where the predicate is on partitioned columns
I have two tables. One a basic table called smallsales defined as below CREATE TABLE `smallsales`( | | `prod_id` bigint, | | `cust_id` bigint, | | `time_id` timestamp, | | `channel_id` bigint, | | `promo_id` bigint, | | `quantity_sold` decimal(10,0), | | `amount_sold` decimal(10,0)) | | ROW FORMAT SERDE | | 'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe' | | STORED AS INPUTFORMAT | | 'org.apache.hadoop.mapred.TextInputFormat' | | OUTPUTFORMAT | | 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat' | | LOCATION | | 'hdfs://rhes564:9000/user/hive/warehouse/oraclehadoop.db/smallsales' | | TBLPROPERTIES ( | | 'COLUMN_STATS_ACCURATE'='true', | | 'last_modified_by'='hduser', | | 'last_modified_time'='1451644705', | | 'numFiles'='1', | | 'numRows'='5000000', | | 'rawDataSize'='193437457', | | 'totalSize'='198437457', | | 'transient_lastDdlTime'='1451784743') | +-------------------------------------------------------------------------+- -+ So 5 million rows. I then created a partitioned table called sales as below | createtab_stmt | +--------------------------------------------------------------------------- ----+--+ | CREATE TABLE `sales`( | | `prod_id` bigint, | | `cust_id` bigint, | | `time_id` timestamp, | | `channel_id` bigint, | | `promo_id` bigint, | | `quantity_sold` decimal(10,0), | | `amount_sold` decimal(10,0)) | | PARTITIONED BY ( | | `year` int, | | `month` int) | | CLUSTERED BY ( | | prod_id, | | cust_id, | | time_id, | | channel_id, | | promo_id) | | INTO 256 BUCKETS | | ROW FORMAT SERDE | | 'org.apache.hadoop.hive.ql.io.orc.OrcSerde' | | STORED AS INPUTFORMAT | | 'org.apache.hadoop.hive.ql.io.orc.OrcInputFormat' | | OUTPUTFORMAT | | 'org.apache.hadoop.hive.ql.io.orc.OrcOutputFormat' | | LOCATION | | 'hdfs://rhes564:9000/user/hive/warehouse/oraclehadoop.db/sales' | | TBLPROPERTIES ( | | 'orc.bloom.filter.columns'='PROD_ID,CUST_ID,TIME_ID,CHANNEL_ID,PROMO_ID', | | 'orc.bloom.filter.fpp'='0.05', | | 'orc.compress'='SNAPPY', | | 'orc.create.index'='true', | | 'orc.row.index.stride'='10000', | | 'orc.stripe.size'='268435456', | | 'transient_lastDdlTime'='1451814921') | +--------------------------------------------------------------------------- ----+--+ And loaded data from smallsales to sales table Stats updated in both Now when I do the following 0: jdbc:hive2://rhes564:10010/default> select * from smallsales where prod_id = 10; +---------------------+---------------------+---------------------+--------- ---------------+----------------------+---------------------------+--------- ----------------+--+ | smallsales.prod_id | smallsales.cust_id | smallsales.time_id | smallsales.channel_id | smallsales.promo_id | smallsales.quantity_sold | smallsales.amount_sold | +---------------------+---------------------+---------------------+--------- ---------------+----------------------+---------------------------+--------- ----------------+--+ +---------------------+---------------------+---------------------+--------- ---------------+----------------------+---------------------------+--------- ----------------+--+ No rows selected (2.231 seconds) Ok if I do the same query from partitioned bucketed table in takes 0: jdbc:hive2://rhes564:10010/default> select * from sales where prod_id = 10; +----------------+----------------+----------------+-------------------+---- -------------+----------------------+--------------------+-------------+---- ----------+--+ | sales.prod_id | sales.cust_id | sales.time_id | sales.channel_id | sales.promo_id | sales.quantity_sold | sales.amount_sold | sales.year | sales.month | +----------------+----------------+----------------+-------------------+---- -------------+----------------------+--------------------+-------------+---- ----------+--+ +----------------+----------------+----------------+-------------------+---- -------------+----------------------+--------------------+-------------+---- ----------+--+ No rows selected (26.96 seconds) Note that the second query is order of magnitude slower. My view is that the query in partitioned table has got to go through every partitioned file to check the existence of the value, whereas in a non-partitioned table the operation is much faster. Adding more partition and buckets also adds more load on NameNode as well. Are there other reasons? Thanks Dr Mich Talebzadeh LinkedIn <https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABU rV8Pw> https://www.linkedin.com/profile/view?id=AAEAAAAWh2gBxianrbJd6zP6AcPCCdOABUr V8Pw Sybase ASE 15 Gold Medal Award 2008 A Winning Strategy: Running the most Critical Financial Data on ASE 15 <http://login.sybase.com/files/Product_Overviews/ASE-Winning-Strategy-091908 .pdf> http://login.sybase.com/files/Product_Overviews/ASE-Winning-Strategy-091908. pdf Author of the books "A Practitioner's Guide to Upgrading to Sybase ASE 15", ISBN 978-0-9563693-0-7. co-author "Sybase Transact SQL Guidelines Best Practices", ISBN 978-0-9759693-0-4 Publications due shortly: Complex Event Processing in Heterogeneous Environments, ISBN: 978-0-9563693-3-8 Oracle and Sybase, Concepts and Contrasts, ISBN: 978-0-9563693-1-4, volume one out shortly <http://talebzadehmich.wordpress.com/> http://talebzadehmich.wordpress.com NOTE: The information in this email is proprietary and confidential. 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