[IMPALA-3674] Lazy materialization of LLVM bitcode

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.6.0
• Component/s: Backend
• Labels: codegen performance
• Target Version: Impala 2.7.0
• Assignee: Michael Ho
• Reporter: Michael Ho
• Created: 04/Jun/16 05:50
• Updated: 26/Jan/17 07:39
• Resolved: 21/Jul/16 00:55

Description

LLVM supports on demand materialization of the bitcode in a module. This helps reduce the preparation time especially for short running queries. Currently, prepare time is a fixed cost of about 140+ ms on my dev box. Lazy materialization can drive this down to 20ms ~ 50ms. This also reduces the time spent in dead code elimination.