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From "Michael Ho (Code Review)" <>
Subject [Impala-ASF-CR] IMPALA-4026: Implement double-buffering for BlockingQueue
Date Wed, 28 Sep 2016 16:50:35 GMT
Hello Tim Armstrong,

I'd like you to reexamine a change.  Please visit

to look at the new patch set (#10).

Change subject: IMPALA-4026: Implement double-buffering for BlockingQueue

IMPALA-4026: Implement double-buffering for BlockingQueue

With recent changes to improve the parquet scanner's efficency,
row batches are produced more quickly, leading to higher contention
in the blocking queue shared between scanner threads and the scan
node. The contention happens between different producers (i.e.
the scanner threads) and also to a lesser extent, between the
scanner threads and the scan node.

This change addresses the contention between the scanner threads
and the scan node by splitting the queue into a 'get_list_' and
a 'put_list_'. The consumers will consume from 'get_list_' until
it's exhausted while the producers will enqueue into 'put_list_'
until it's full. When 'get_list_' is exhausted, the consumer will
atomically swap the 'get_list_' with 'put_list_'. This reduces
the contention: 'get_list_' and 'put_list_' are protected by two
different locks so callers of BlockingGet() only contends for the
'put_lock_' when 'put_list_' is empty.

With this change, primitive_filter_bigint_non_selective improves
by 33.9%, going from 1.60s to 1.06s

Change-Id: Ib9f4cf351455efefb0f3bb791cf9bc82d1421d54
M be/src/common/compiler-util.h
M be/src/exec/
M be/src/exec/hdfs-scan-node.h
M be/src/util/blocking-queue.h
A be/src/util/condition-variable.h
M be/src/util/thread-pool.h
6 files changed, 221 insertions(+), 66 deletions(-)

  git pull ssh:// refs/changes/50/4350/10
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ib9f4cf351455efefb0f3bb791cf9bc82d1421d54
Gerrit-PatchSet: 10
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Michael Ho <>
Gerrit-Reviewer: Alex Behm <>
Gerrit-Reviewer: Chen Huang <>
Gerrit-Reviewer: Dan Hecht <>
Gerrit-Reviewer: Juan Yu <>
Gerrit-Reviewer: Michael Ho <>
Gerrit-Reviewer: Mostafa Mokhtar <>
Gerrit-Reviewer: Tim Armstrong <>

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