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https://issues.apache.org/jira/browse/HBASE-17958?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15983917#comment-15983917
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Duo Zhang commented on HBASE-17958:
-----------------------------------
The idea is good, and converting seek to skip is a common optimization.
The 'bad practice' here is the way we implement it. If the MatchCode is
SEEK_NEXT_ROW or SEEK_NEXT_COL, no matter how you done the seek, either by a
real seek or a sequence of skips, you should stop passing the cell in the same
row or same column to the SQM, otherwise you should change the MatchCode to
TRY_SEEK_NEXT_ROW and TRY_SEEK_NEXT_COL. It is really confusing.
That's my point.
Thanks.
> 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
>
> {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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