[HIVE-5483] use metastore statistics to optimize max/min/etc. queries

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.13.0
• Assignee: Ashutosh Chauhan
• Reporter: Sergey Shelukhin
• Created: 07/Oct/13 22:33
• Updated: 30/Jul/16 20:29
• Resolved: 31/Oct/13 21:22

Description

We have discussed this a little bit.
Hive can answer queries such as select max(c1) from t purely from metastore using partition statistics, provided that we know the statistics are up to date.
All data changes (e.g. adding new partitions) currently go thru metastore so we can track up-to-date-ness. If they are not up-to-date, the queries will have to read data (at least for outdated partitions) until someone runs analyze table. We can also analyze new partitions after add, if that is configured/specified in the command.

Issue Links

• incorporates: HIVE-6192 Optimize sum(1) to answer query using metadata