[HIVE-416] Get rid of backtrack in Hive.g

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.4.0
• Fix Version/s: 0.4.0
• Component/s: Query Processor
• Hadoop Flags: Reviewed
• Assignee: Zheng Shao
• Reporter: Zheng Shao
• Created: 15/Apr/09 07:08
• Updated: 17/Dec/11 00:07
• Resolved: 18/Apr/09 06:08

Description

Hive.g now still uses "backtrack=true". "backtrack" not only slows down the parsing in case of error, it can also produce wrong syntax error messages (usually based on the last try of the backtracking).

We should follow http://www.antlr.org/wiki/display/ANTLR3/How+to+remove+global+backtracking+from+your+grammar to remove the need of doing backtrack.

Issue Links

• is blocked by: HIVE-415 Long queries does not parse in Hive
• relates to: HIVE-424 PartitionPruner fails with "WHERE ds = '2009-03-01'"