[ https://issues.apache.org/jira/browse/SPARK-21520?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Apache Spark reassigned SPARK-21520: ------------------------------------ Assignee: (was: Apache Spark) > Hivetable scan for all the columns the SQL statement contains the 'rand' > ------------------------------------------------------------------------ > > Key: SPARK-21520 > URL: https://issues.apache.org/jira/browse/SPARK-21520 > Project: Spark > Issue Type: Improvement > Components: SQL > Affects Versions: 2.3.0 > Reporter: caoxuewen > > Currently, when the rand function is present in the SQL statement, hivetable > searches all columns in the table. > e.g: > select k,k,sum(id) from (select d004 as id, floor(rand() * 10000) as k, > ceil(c010) as cceila from XXX_table) a > group by k,k; > generate WholeStageCodegen subtrees: > == Subtree 1 / 2 == > *HashAggregate(keys=[k#403L], functions=[partial_sum(cast(id#402 as > bigint))], output=[k#403L, sum#800L]) > +- Project [d004#607 AS id#402, FLOOR((rand(8828525941469309371) * 10000.0)) > AS k#403L] > +- HiveTableScan [c030#606L, d004#607, d005#608, d025#609, c002#610, > d023#611, d024#612, c005#613L, c008#614, c009#615, c010#616, d021#617, > d022#618, c017#619, c018#620, c019#621, c020#622, c021#623, c022#624, > c023#625, c024#626, c025#627, c026#628, c027#629, ... 169 more fields], > MetastoreRelation XXX_database, XXX_table > == Subtree 2 / 2 == > *HashAggregate(keys=[k#403L], functions=[sum(cast(id#402 as bigint))], > output=[k#403L, k#403L, sum(id)#797L]) > +- Exchange hashpartitioning(k#403L, 200) > +- *HashAggregate(keys=[k#403L], functions=[partial_sum(cast(id#402 as > bigint))], output=[k#403L, sum#800L]) > +- Project [d004#607 AS id#402, FLOOR((rand(8828525941469309371) * > 10000.0)) AS k#403L] > +- HiveTableScan [c030#606L, d004#607, d005#608, d025#609, c002#610, > d023#611, d024#612, c005#613L, c008#614, c009#615, c010#616, d021#617, > d022#618, c017#619, c018#620, c019#621, c020#622, c021#623, c022#624, > c023#625, c024#626, c025#627, c026#628, c027#629, ... 169 more fields], > MetastoreRelation XXX_database, XXX_table > > All columns will be searched in HiveTableScans , Consequently, All column > data is read to a ORC table. > e.g: > INFO ReaderImpl: Reading ORC rows from > hdfs://opena:8020/.../XXX_table/.../p_date=2017-05-25/p_hour=10/part-00009 > with {include: [true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true, true, true, true, true, true, true, > true, true, true, true, true, true, true], offset: 0, length: > 9223372036854775807} > so, The execution of the SQL statement will become very slow. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org