Hello Michael Ho, Thomas Tauber-Marshall, Dan Hecht,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/5400
to look at the new patch set (#10).
Change subject: IMPALA-3989: Display skew warning for poorly formatted Parquet
files
......................................................................
IMPALA-3989: Display skew warning for poorly formatted Parquet files
Parquet files are scanned in the granularity of row groups. Each row
group belongs to one or more splits and each split is scanned by a
separate parquet scanner.
If some row groups span multiple splits, then we will most likely end
up seeing some scanners having remote reads and some scanners not
performing scans at all. This will attribute to skew across the
cluster where distribution of scans is uneven.
This change adds a counter (NumScannersWithNoReads) to the scan node's
runtime profile to track the number of parquet scanners that end up
doing no reads becuse of poor formatting.
Change-Id: Ibf48d978383d73efdade733a892e795ebd53c76a
---
M be/src/exec/hdfs-parquet-scanner.cc
M be/src/exec/hdfs-parquet-scanner.h
M tests/query_test/test_scanners.py
3 files changed, 113 insertions(+), 9 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/00/5400/10
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ibf48d978383d73efdade733a892e795ebd53c76a
Gerrit-PatchSet: 10
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Attila Jeges <[email protected]>
Gerrit-Reviewer: Attila Jeges <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Michael Ho <[email protected]>
Gerrit-Reviewer: Sailesh Mukil <[email protected]>
Gerrit-Reviewer: Thomas Tauber-Marshall <[email protected]>
