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https://issues.apache.org/jira/browse/HBASE-17958?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16446908#comment-16446908
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Lars Hofhansl edited comment on HBASE-17958 at 5/12/18 10:59 PM:
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Seems we got stuck here. [~vik.karma] did some comparative testing between 0.98
and 1.x and found a 50% slowdown for cases with many columns. This is a highly
likely culprit.
was (Author: lhofhansl):
Seems we god stuck here. [~vik.karma] did some comparative testing between 0.98
and 1.x and found a 50% slowdown for cases with many columns. This is a highly
likely culprit.
> Avoid passing unexpected cell to ScanQueryMatcher when optimize SEEK to SKIP
> ----------------------------------------------------------------------------
>
> Key: HBASE-17958
> URL: https://issues.apache.org/jira/browse/HBASE-17958
> Project: HBase
> Issue Type: Bug
> Reporter: Guanghao Zhang
> Assignee: Guanghao Zhang
> Priority: Major
> Fix For: 1.4.0, 2.0.0
>
> Attachments: 0001-add-one-ut-testWithColumnCountGetFilter.patch,
> 17958-add.txt, HBASE-17958-branch-1.patch, HBASE-17958-branch-1.patch,
> HBASE-17958-branch-1.patch, HBASE-17958-branch-1.patch, HBASE-17958-v1.patch,
> HBASE-17958-v2.patch, HBASE-17958-v3.patch, HBASE-17958-v4.patch,
> HBASE-17958-v5.patch, HBASE-17958-v6.patch, HBASE-17958-v7.patch,
> HBASE-17958-v7.patch
>
>
> {code}
> ScanQueryMatcher.MatchCode qcode = matcher.match(cell);
> qcode = optimize(qcode, cell);
> {code}
> The optimize method may change the MatchCode from SEEK_NEXT_COL/SEEK_NEXT_ROW
> to SKIP. But it still pass the next cell to ScanQueryMatcher. It will get
> wrong result when use some filter, etc. ColumnCountGetFilter. It just count
> the columns's number. If pass a same column to this filter, the count result
> will be wrong. So we should avoid passing cell to ScanQueryMatcher when
> optimize SEEK to SKIP.
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