Hello Kudu Jenkins,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/4164
to look at the new patch set (#3).
Change subject: Inlined dispatch for predicate evaluation
......................................................................
Inlined dispatch for predicate evaluation
In order to evaluate a predicate, we must first determine the correct
comparator to handle the physical type of interest. Currently, this
occurs once per batch when ColumnPredicate::Evaluate() is called. A
call to this will dispatch the comparator as a lambda to be applied in
a loop over all rows in the batch.
For ColumnPredicate::EvaluateCell(), rather than occuring in batches,
dispatch occurs for each cell. This particularly slows down
decoder-level evaluation, which falls back on evaluating cell-by-cell
rather than in batches. To remediate this, the dispatch has been
templatized here to remediate the cost of repeated dispatch.
This figure shows the performance of dictionary encoding for
decoder-level evaluation without this templating adjustment. The query
selects a single value out of a dictionary-encoded column containing
1M unique strings.
https://raw.githubusercontent.com/anjuwong/kudu/300f1e8bdf05bc16bdacacca22482e579e49de67/docs/images/SELECT_OUTSIDE_OF_RANGE_non_inlined.png
Compare the above with the plot on the right, which is the result of
the same query, but with inlined dispatch.
https://raw.githubusercontent.com/anjuwong/kudu/300f1e8bdf05bc16bdacacca22482e579e49de67/docs/images/SELECT_OUTSIDE_OF_RANGE_inlined.png
Change-Id: Iccfac9bc899362b442337050795b5ca8c4101268
---
M src/kudu/cfile/binary_plain_block.cc
M src/kudu/cfile/cfile_reader.cc
M src/kudu/common/column_predicate.cc
M src/kudu/common/column_predicate.h
4 files changed, 103 insertions(+), 42 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/64/4164/3
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Iccfac9bc899362b442337050795b5ca8c4101268
Gerrit-PatchSet: 3
Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-Owner: Andrew Wong <andrew.w...@cloudera.com>
Gerrit-Reviewer: Alexey Serbin <aser...@cloudera.com>
Gerrit-Reviewer: Andrew Wong
Gerrit-Reviewer: Dan Burkert <d...@cloudera.com>
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Todd Lipcon <t...@apache.org>
