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https://issues.apache.org/jira/browse/HBASE-13109?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14346217#comment-14346217
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Lars Hofhansl edited comment on HBASE-13109 at 3/4/15 1:53 AM:
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Same, but with each column in its own CF (in this case Phoenix does not use its
WildcardTracker + Filter optimization)
6CF case:
|| ||q1||q2||
|w/o patch|15.3|15.5|
|w/ patch|9.14|9.19|
Any objection committing this to all branches?
([~stack], [~apurtell], [~ram_krish]?)
[~giacomotaylor], FYI (we can probably remove the ColumnProjectionFilter
optimization when this is in)
was (Author: lhofhansl):
Same, but with each column in its own CF (in this case Phoenix does not use its
WildcardTracker + Filter optimization)
6CF case:
|| ||q1||q2||
|w/o patch|15.3|15.5|
|w/ patch|9.14|9.19|
Any objection committing this to all branches.
[~giacomotaylor], FYI (we can probably remove the ColumnProjectionFilter
optimization when this is in)
> Make better SEEK vs SKIP decisions during scanning
> --------------------------------------------------
>
> Key: HBASE-13109
> URL: https://issues.apache.org/jira/browse/HBASE-13109
> Project: HBase
> Issue Type: Bug
> Reporter: Lars Hofhansl
> Assignee: Lars Hofhansl
> Priority: Minor
> Attachments: 13109-0.98-v4.txt, 13109-trunk-v2.txt,
> 13109-trunk-v3.txt, 13109-trunk-v4.txt, 13109-trunk-v5.txt, 13109-trunk.txt,
> nextIndexKVChange_new.patch
>
>
> I'm re-purposing this issue to add a heuristic as to when to SEEK and when to
> SKIP Cells. This has come up in various issues, and I think I have a way to
> finally fix this now. HBASE-9778, HBASE-12311, and friends are related.
> --- Old description ---
> This is a continuation of HBASE-9778.
> We've seen a scenario of a very slow scan over a region using a timerange
> that happens to fall after the ts of any Cell in the region.
> Turns out we spend a lot of time seeking.
> Tested with a 5 column table, and the scan is 5x faster when the timerange
> falls before all Cells' ts.
> We can use the lookahead hint introduced in HBASE-9778 to do opportunistic
> SKIPing before we actually seek.
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