Riza Suminto has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/18126 )

Change subject: IMPALA-11068: Add tuning flag to reduce scanner thread launch.
......................................................................


Patch Set 1:

> Patch Set 1:
>
> Should we look into making the constant COMPRESSED_TEXT_COMPRESSION_RATIO 
> tunable in hdfs-scan-node.cc instead?

COMPRESSED_TEXT_COMPRESSION_RATIO is only used when reading file with text 
format (THdfsFileFormat::TEXT).
For non-text format, it will use hdfs_scanner_thread_max_estimated_bytes which 
default to 32MB.

Customer hit OOM over parquet file format. They have try increase 
hdfs_scanner_thread_max_estimated_bytes higher, but that leads to performance 
regression for other queries.


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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I03cadf1230eed00d69f2890c82476c6861e37466
Gerrit-Change-Number: 18126
Gerrit-PatchSet: 1
Gerrit-Owner: Riza Suminto <[email protected]>
Gerrit-Reviewer: Bikramjeet Vig <[email protected]>
Gerrit-Reviewer: Joe McDonnell <[email protected]>
Gerrit-Reviewer: Riza Suminto <[email protected]>
Gerrit-Comment-Date: Sat, 08 Jan 2022 03:48:39 +0000
Gerrit-HasComments: No

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