[IMPALA-2939] Nested Types : Address Runtime & Scoped timer overhead

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: Impala 2.4.0
• Component/s: Backend
• Labels: complextype nested_types performance
• Epic Link: Complex types performance improvements
• Target Version: Product Backlog
• Assignee: Unassigned
• Reporter: Mostafa Mokhtar
• Created: 04/Feb/16 00:07
• Updated: 16/Mar/20 16:57

Description

For the following query about 45% of the time is spent in updating timers, RunTimeProfile and checking query state, since NestedTypes don't always operate on Batches the overhead of updating counters is amplified.

select 
    l.l_shipdate, count(*) as wins
from
    customer.c_orders o,
    o.o_lineitems l
where
    o_orderdate = '1993-12-12'
group by l.l_shipdate
order by wins;

Function	Effective Time by Utilization
clock_gettime 29.8% 0s 0s librt.so.1	clock_gettime
impala::RuntimeProfile::Counter::Add	5.3%
std::map<std::string, impala::RuntimeProfile::Counter*, std::less<std::string>, std::allocator<std::pair<std::string const, impala::RuntimeProfile::Counter*>>>::operator[]	4.7%
impala::RuntimeState::CheckQueryState	3.2%
impala::MonotonicStopWatch::Stop	2.7%