Hello Tim Armstrong, Dan Hecht, Impala Public Jenkins,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/11270
to look at the new patch set (#2).
Change subject: IMPALA-7422: Fix a race in QueryState::StartFInstances()
......................................................................
IMPALA-7422: Fix a race in QueryState::StartFInstances()
A recent commit for IMPALA-7163 (cbc8c63) introduced a race between
insertion into QueryState::fragment_map_ and the thread creation.
In particular, after the aforementioned commit, the counting barrier
'instances_prepared_barrier_' is used for synchronizing callers of
Cancel() and PublishFilter() and the PREPARE phase of fragment instances.
Cancel() and PublishFilter() cannot proceed until all fragment instances
have finished preparing; 'instances_prepared_barrier_' is updated by
fragment instances once each of them is done preparing.
The race is due to the fact that QueryState::StartFInstances() doesn't
insert the fragment instance into 'fragment_map_' until after the fragment
instance thread has been spawned. So, it's possible for the newly spawned
thread to finish preparing and update the counting barrier before the insertion
into 'fragment_map_' happens. It's therefore possible for, PublishFilter() to
have gotten unblocked before a fragment is inserted into 'fragment_map_',
triggering the DCHECK() in IMPALA-7422.
This change fixes the race by moving the insertion into fragment_map_
before the thread is spawned.
Testing done: Exhaustive debug + release builds which previously ran into this
race
Change-Id: I35f2a5b0ea5143703850ffc229cec0e4294e6a3e
---
M be/src/runtime/query-state.cc
M be/src/runtime/query-state.h
2 files changed, 13 insertions(+), 7 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/70/11270/2
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I35f2a5b0ea5143703850ffc229cec0e4294e6a3e
Gerrit-Change-Number: 11270
Gerrit-PatchSet: 2
Gerrit-Owner: Michael Ho <k...@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com>
Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com>
