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From "Philip Zeyliger (Code Review)" <>
Subject [Impala-ASF-CR] IMPALA-6070: Parallel compute table
Date Mon, 23 Oct 2017 18:43:07 GMT
Hello Michael Brown, David Knupp, Alex Behm, 

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

to look at the new patch set (#4).

Change subject: IMPALA-6070: Parallel

IMPALA-6070: Parallel

Uses a thread pool to issue many compute stats commands in parallel to
Impala, rather than doing it serially. Where it was obvious, I combined
multiple stats commands into fewer, to reduce the number
of "show databses" and serialized "show tables" commands.

This speeds up the compute stats step in data loading significantly. My
measurements for testdata/bin/ running before and
after this change, with the Impala daemons restarted (cold) or not
restarted (warm) on an 8-core, 32GB RAM machine were:

old, cold: 7m44s
new, cold: 1m42s

old, warm: 1m23s
new, warm:   48s

The data load in the full test build behaves in a cold fashion. It's
typical for to
run this compute stats step for 9 or 10 minutes. With this change, this
will come down to about 2 minutes.

Change-Id: Ifb080f2552b9dbe304ecadd6e52429214094237d
M testdata/bin/
M tests/util/
2 files changed, 59 insertions(+), 30 deletions(-)

  git pull ssh:// refs/changes/54/8354/4
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ifb080f2552b9dbe304ecadd6e52429214094237d
Gerrit-Change-Number: 8354
Gerrit-PatchSet: 4
Gerrit-Owner: Philip Zeyliger <>
Gerrit-Reviewer: Alex Behm <>
Gerrit-Reviewer: David Knupp <>
Gerrit-Reviewer: Michael Brown <>
Gerrit-Reviewer: Philip Zeyliger <>

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