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From "Pranay Singh (Code Review)" <>
Subject [Impala-ASF-CR] IMPALA-5522:Use tracked memory for DictDecoder and DictEncoder
Date Thu, 14 Dec 2017 17:52:00 GMT
Hello Taras Bobrovytsky, Joe McDonnell, Tim Armstrong, Bikramjeet Vig, Impala Public Jenkins,

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

to look at the new patch set (#19).

Change subject: IMPALA-5522:Use tracked memory for DictDecoder and DictEncoder

IMPALA-5522:Use tracked memory for DictDecoder and DictEncoder

Currently DictDecoder class and DictEncoder class uses std::vector
to store the tables mapping codeword to value and vice-versa. It is
hard to detect the memory usage by these tables when they becomes
very large, since this memory is not accounted by Impala's memory
mangement infrastructure.

This patch uses the memory tracker of HdfsScanner to track the memory used
by dictionary in DictDecoder class. Similary it uses memory tracker of
HdfsTableSink to track the memory used by dictionary in DictEncoder class.

Memory for the dictionary, stored as std::vector is still allocated
from std:allocator but the amount allocated is accounted by
introducing a counter which is incremented and decremented as the
memory is consumed and released by vector.

Ran all the backend and end-end tests with no failures.

Change-Id: I02a3b54f6c107d19b62ad9e1c49df94175964299
M be/src/exec/
M be/src/exec/
M be/src/exec/parquet-column-readers.h
M be/src/util/dict-encoding.h
M be/src/util/
5 files changed, 173 insertions(+), 24 deletions(-)

  git pull ssh:// refs/changes/34/8034/19
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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I02a3b54f6c107d19b62ad9e1c49df94175964299
Gerrit-Change-Number: 8034
Gerrit-PatchSet: 19
Gerrit-Owner: Pranay Singh
Gerrit-Reviewer: Bikramjeet Vig <>
Gerrit-Reviewer: Impala Public Jenkins
Gerrit-Reviewer: Joe McDonnell <>
Gerrit-Reviewer: Pranay Singh
Gerrit-Reviewer: Taras Bobrovytsky <>
Gerrit-Reviewer: Tim Armstrong <>

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