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From "Impala Public Jenkins (Code Review)" <>
Subject [Impala-ASF-CR] IMPALA-5304: reduce transfer of Parquet decompression buffers
Date Mon, 22 May 2017 10:39:13 GMT
Impala Public Jenkins has submitted this change and it was merged.

Change subject: IMPALA-5304: reduce transfer of Parquet decompression buffers

IMPALA-5304: reduce transfer of Parquet decompression buffers

The buffers contain the Parquet DataPages, which need to be
attached to the row batch if the rows point to var-len data
stored directly in the page. Otherwise the buffers can be
discarded once the values in the page have been materialized.

This reduces the amount of memory transferred between threads, which is
a known TCMalloc anti-pattern. It also allows us to free memory
earlier, which may help reduce memory consumption slightly.

Also fix a latent bug I noticed where needs_conversion_ is not
always initialised in the constructor.

Ran exhaustive build. Most of the Parquet tests use compressed Parquet,
which should exercise this code path.

Change-Id: I2dbd749f43078b222ff8e1ddcec840986c466de6
Reviewed-by: Tim Armstrong <>
Tested-by: Impala Public Jenkins
M be/src/exec/
M be/src/exec/parquet-column-readers.h
2 files changed, 18 insertions(+), 4 deletions(-)

  Impala Public Jenkins: Verified
  Tim Armstrong: Looks good to me, approved

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Gerrit-MessageType: merged
Gerrit-Change-Id: I2dbd749f43078b222ff8e1ddcec840986c466de6
Gerrit-PatchSet: 7
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <>
Gerrit-Reviewer: Alex Behm <>
Gerrit-Reviewer: Impala Public Jenkins
Gerrit-Reviewer: Michael Ho <>
Gerrit-Reviewer: Tim Armstrong <>

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