[
https://issues.apache.org/jira/browse/KUDU-2844?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17178068#comment-17178068
]
ASF subversion and git services commented on KUDU-2844:
-------------------------------------------------------
Commit fb0f4bc3bf63614a831fedc6cc29cf860dddaf49 in kudu's branch
refs/heads/master from Todd Lipcon
[ https://gitbox.apache.org/repos/asf?p=kudu.git;h=fb0f4bc ]
KUDU-2844 (2/3): move RowBlock memory into a new RowBlockMemory struct
This takes the Arena* member of RowBlock and moves it into a new
RowBlockMemory structure. The RowBlockMemory structure will later
be extended to include a list of reference-counted block handles.
Change-Id: I17a21f33f44988795ffe064b3ba41055e1a19e90
Reviewed-on: http://gerrit.cloudera.org:8080/15801
Reviewed-by: Andrew Wong <[email protected]>
Tested-by: Kudu Jenkins
> Avoid copying strings from dictionary or plain-encoded blocks
> -------------------------------------------------------------
>
> Key: KUDU-2844
> URL: https://issues.apache.org/jira/browse/KUDU-2844
> Project: Kudu
> Issue Type: Improvement
> Components: cfile, perf
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Priority: Major
> Attachments: fg.svg
>
>
> When scanning a plain or dictionary-encoded binary column, we currently loop
> over each entry and copy the string into the destination RowBlock's arena. In
> TPCH Q1, the scanner threads use a significant percentage of CPU doing this
> copying, and it also increases CPU cache footprint which likely decreases
> performance in downstream operations like predicate evaluation, merging,
> result serialization, etc.
> Instead of doing this, we could "attach" the dictionary block (with
> ref-counting) to the RowBlock and refer directly to the dictionary entry from
> the RowBlock. When the RowBlock eventually is reset, we can drop the
> reference. This should be safe because we never mutate indirect data in-place.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
