[HIVE-23907] Hash table type should be considered for calculating the Map join table size

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Assignee: mahesh kumar behera
• Reporter: mahesh kumar behera
• Created: 23/Jul/20 07:04
• Updated: 23/Jul/20 07:09

Description

For some join like Anti join and Semi join , hash set is used instead of a hash table. This is done as these joins do not emit the right side columns and just an existence check is enough for join.  When we check for the  table size , during map join conversion , this info is not considered. The hash table size for these join will be considerably small and thus hash table for bigger table can fit into memory.

 

Issue Links

• is related to: HIVE-23716 Support Anti Join in Hive