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liyunzhang_intel commented on HIVE-16602: ----------------------------------------- [~jcamachorodriguez]: I am envaluating the the performance improvement of HIVE-16602 on tez i use tpcds compare the execution time in the package without HIVE-16602 and with HIVE-16602 on 10g data scale. I guess there is improvement with this feature as it only loads table once even it appears multiple time in the query. Have you done some benchmark test about this feature? > Implement shared scans with Tez > ------------------------------- > > Key: HIVE-16602 > URL: https://issues.apache.org/jira/browse/HIVE-16602 > Project: Hive > Issue Type: New Feature > Components: Physical Optimizer > Affects Versions: 3.0.0 > Reporter: Jesus Camacho Rodriguez > Assignee: Jesus Camacho Rodriguez > Labels: TODOC3.0 > Fix For: 3.0.0 > > Attachments: HIVE-16602.01.patch, HIVE-16602.02.patch, > HIVE-16602.03.patch, HIVE-16602.04.patch, HIVE-16602.patch > > > Given a query plan, the goal is to identify scans on input tables that can be > merged so the data is read only once. Optimization will be carried out at the > physical level. > In the longer term, identification of equivalent expressions and > reutilization of intermediary results should be done at the logical layer via > Spool operator. -- This message was sent by Atlassian JIRA (v6.4.14#64029)