[ http://issues.apache.org/jira/browse/DERBY-772?page=comments#action_12360985 ]
Daniel John Debrunner commented on DERBY-772: --------------------------------------------- -1 due to regression, see comments in DERBY-649 > Handle pushing IN predicates into UNIONs. This would allow use of index if > present improving performance. > --------------------------------------------------------------------------------------------------------- > > Key: DERBY-772 > URL: http://issues.apache.org/jira/browse/DERBY-772 > Project: Derby > Type: Sub-task > Components: SQL > Versions: 10.0.2.0, 10.1.2.1, 10.2.0.0 > Environment: generic > Reporter: Satheesh Bandaram > Fix For: 10.2.0.0, 10.1.2.2 > Attachments: DERBY-772.patch > > While fix for DERBY-649 allows pushing binary predicates into SELECT > statements that are underneath a UNOIN, it would also be good to allow IN > operations to be pushed. Derby can rewrite IN operations in a way to allow > use of index, if present. > Derby currently rewrites: REF IN (1, 2, 3) to REF >=1 and REF <=3 and hence > would allow use of index on REF, if present. Pushing this predicate into > Union would allow use of index on REF for queries like: > Select * from > (SELECT REF, NAME from T1 UNION ALL SELECT REF, NAME from t2) > where REF IN (1,2,3) -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
