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https://issues.apache.org/jira/browse/HBASE-9079?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13723305#comment-13723305
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Viral Bajaria commented on HBASE-9079:
--------------------------------------
I will upload a new patch with the fixes that Ted pointed out.
[~te...@apache.org] When you say trunk patch you mean against the 0.95/0.96
tree ?
Regards Lars comment on turning it around to ==, I could move it to the
following prior to even running the for loop:
{code}
if (seekHintFilter != null) {
return seekHintFilter.getNextKeyHint();
}
{code}
Regarding the ordering, I think the issue will be when operator is
MUST_PASS_ONE and both filters want to give you a SEEK_HINT but one of them is
operating at the row level while the other is operating at the column level.
For example, if ColumnRange comes before FuzzyRow and operator is
MUST_PASS_ONE, we will iterate through both the filters filterKeyValue method
and keep the state returned from FuzzyRow and not from ColumnRange. I think
this issue exists in current code too since we go through each filter and keep
the max row.
Personally I feel it's not a good use-case to make a FilterList with one filter
operating at the row level and another at the column level and asking the
operator to be MUST_PASS_ONE. That's almost like saying that keep a column even
if row does not match. Any suggestions on what should be done here ?
> FilterList getNextKeyHint skips rows that should be included in the results
> ---------------------------------------------------------------------------
>
> Key: HBASE-9079
> URL: https://issues.apache.org/jira/browse/HBASE-9079
> Project: HBase
> Issue Type: Bug
> Components: Filters
> Affects Versions: 0.94.10
> Reporter: Viral Bajaria
> Attachments: TestFail.patch, TestSuccess.patch
>
>
> I hit a weird issue/bug and am able to reproduce the error consistently. The
> problem arises when FilterList has two filters where each implements the
> getNextKeyHint method.
> The way the current implementation works is, StoreScanner will call
> matcher.getNextKeyHint() whenever it gets a SEEK_NEXT_USING_HINT. This in
> turn will call filter.getNextKeyHint() which at this stage is of type
> FilterList. The implementation in FilterList iterates through all the filters
> and keeps the max KeyValue that it sees. All is fine if you wrap filters in
> FilterList in which only one of them implements getNextKeyHint. but if
> multiple of them implement then that's where things get weird.
> For example:
> - create two filters: one is FuzzyRowFilter and second is ColumnRangeFilter.
> Both of them implement getNextKeyHint
> - wrap them in FilterList with MUST_PASS_ALL
> - FuzzyRowFilter will seek to the correct first row and then pass it to
> ColumnRangeFilter which will return the SEEK_NEXT_USING_HINT code.
> - Now in FilterList when getNextKeyHint is called, it calls the one on
> FuzzyRow first which basically says what the next row should be. While in
> reality we want the ColumnRangeFilter to give the seek hint.
> - The above behavior skips data that should be returned, which I have
> verified by using a RowFilter with RegexStringComparator.
> I updated the FilterList to maintain state on which filter returns the
> SEEK_NEXT_USING_HINT and in getNextKeyHint, I invoke the method on the saved
> filter and reset that state. I tested it with my current queries and it works
> fine but I need to run the entire test suite to make sure I have not
> introduced any regression. In addition to that I need to figure out what
> should be the behavior when the opeation is MUST_PASS_ONE, but I doubt it
> should be any different.
> Is my understanding of it being a bug correct ? Or am I trivializing it and
> ignoring something very important ? If it's tough to wrap your head around
> the explanation, then I can open a JIRA and upload a patch against 0.94 head.
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