[jira] [Commented] (IMPALA-9612) Runtime filter wait longer than it should be

["Tim Armstrong (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IMPALA-9612?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17077349#comment-17077349 ] 

Tim Armstrong commented on IMPALA-9612:
---------------------------------------

I think the race is similar to IMPALA-9611, where the writer doesn't hold the lock at any time between setting the atomic and signalling the CV. This allows the race I described on that JIRA.

> Runtime filter wait longer than it should be
> --------------------------------------------
>
>                 Key: IMPALA-9612
>                 URL: https://issues.apache.org/jira/browse/IMPALA-9612
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Backend
>            Reporter: Riza Suminto
>            Assignee: Riza Suminto
>            Priority: Major
>
> In one of my query profile, I found an info string like this:
>   Runtime filters: All filters arrived. Waited 59s783ms. Maximum arrival delay: 15s296ms.
> If all runtime filters arrived within 15s296ms, then it should not wait until 59s783ms to proceed.
> Looking at runtime-filter.cc, It looks like there is a potential race condition in function RuntimeFilter::WaitForArrival().
> bool RuntimeFilter::WaitForArrival(int32_t timeout_ms) const {
>   unique_lock<mutex> l(arrival_mutex_);
>   while (arrival_time_.Load() == 0) {
>     int64_t ms_since_registration = MonotonicMillis() - registration_time_;
>     int64_t ms_remaining = timeout_ms - ms_since_registration;
>     if (ms_remaining <= 0) break;
>     arrival_cv_.WaitFor(l, ms_remaining * MICROS_PER_MILLI);
>   }
>   return arrival_time_.Load() != 0;
> }
> Between checking arrival_time_.Load() and calling arrival_cv_.WaitFor(), arrival_cv_ might be already signaled by either RuntimeFilter::SetFilter() or RuntimeFilter::Cancel() because they do not acquire arrival_mutex_ first.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org