[IMPALA-3553] LLVM CodeGen performanc​e reduced

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Cannot Reproduce
• Affects Version/s: Impala 2.0, Impala 2.2
• Component/s: Backend
• Target Version: Product Backlog
• Assignee: Unassigned
• Reporter: seven chen
• Created: 17/May/16 07:33
• Updated: 23/Nov/17 00:10
• Resolved: 23/Nov/17 00:10

Description

when impala running about 3 months,the same sql will become slowly.

According to the profile,i see the compile_timer_ take about 2m32s.

The code detail is below.
SCOPED_TIMER(compile_timer_);
// JIT compile all codegen'd functions
for (int i = 0; i < fns_to_jit_compile_.size(); ++i)

{ *fns_to_jit_compile_[i].second = JitFunction(fns_to_jit_compile_[i].first); }

If reboot the impala,CodeGen performance will normal.