[HIVE-4572] ColumnPruner cannot preserve RS key columns corresponding to un-selected join keys in columnExprMap

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.12.0
• Fix Version/s: 0.12.0
• Tags: ColumnPruner
• Assignee: Yin Huai Assign to me
• Reporter: Yin Huai
• Created: 16/May/13 17:55
• Updated: 15/Oct/13 23:31
• Resolved: 28/May/13 00:59

Description

For a RS of a join operator, if the join key corresponding to this RS does not appear in the SELECT clause, ColumnPruner will drop the entry of this column in colExprMap.

Example:

SELECT x.key FROM src1 x JOIN src y ON (x.key = y.key);

Before CP,

colExprMap of RS corresponding to x: {VALUE._col3=Column[INPUT__FILE__NAME], VALUE._col2=Column[BLOCK__OFFSET__INSIDE__FILE], VALUE._col1=Column[value], VALUE._col0=Column[key]};
colExprMap of RS corresponding to y: {VALUE._col3=Column[INPUT__FILE__NAME], VALUE._col2=Column[BLOCK__OFFSET__INSIDE__FILE], VALUE._col1=Column[value], VALUE._col0=Column[key]}.

After CP,

colExprMap of RS corresponding to x: {VALUE._col0=Column[key]};
colExprMap of RS corresponding to y: {}.

Issue Links

• blocks: HIVE-2206 add a new optimizer for query correlation discovery and optimization