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HBase, mail # user - Custom Filter and SEEK_NEXT_USING_HINT issue


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Re: Custom Filter and SEEK_NEXT_USING_HINT issue
Ted Yu 2013-01-18, 23:56
To my knowledge CDH-4.1.2 is based on HBase 0.92.x

Looks like you were using patch from HBASE-6509 which was integrated to
trunk only.
Please confirm.

Copying Alex who wrote the patch.

Cheers

On Fri, Jan 18, 2013 at 3:28 PM, Eugeny Morozov
<[EMAIL PROTECTED]>wrote:

> Hi, folks!
>
> HBase, Hadoop, etc version is CDH-4.1.2
>
> I'm using custom FuzzyRowFilter, which I get from
>
> http://blog.sematext.com/2012/08/09/consider-using-fuzzyrowfilter-when-in-need-for-secondary-indexes-in-hbase/and
> suddenly after quite a time we found that it starts loosing data.
>
> Basically the idea of FuzzyRowFilter is that it tries to find key that has
> been provided and if there is no such a key - but more exists in table - it
> returns SEEK_NEXT_USING_HINT. And in getNextKeyHint(...) it builds required
> key. As I understand, HBase in this key will fast-forward to required key -
> it must be similar or same as to get Scan with setStartRow.
>
> I'm trying to find key F7dt8QWPSIDw, it is definitely in HBase - I'm able
> to get it using Scan.setStartRow.
> For FuzzyFilter I'm using empty Scan - I didn't specify start row, stop row
> or anything related.
> That's what happening:
>
> Fzzy: AAAA1Q7iQ9JA
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: AQAAnA96rxTg
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: AgAADQWPSIDw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: AwAA-Q33Zb9Q
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: BAAAOg8oyu7A
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: BQAA9gqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: BgABZQ7iQ9JA
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: BwAAbgrpAojg
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: CAAAUQWPSIDw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: CQABVgqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: CgAAOQ7iQ9JA
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: CwAALwqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: DAAAMwWPSIDw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: DQAADgjqzsIQ
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: DgAAOgCcWv9g
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: DwAAKg7iQ9JA
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: EAAAugqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: EQAAJAqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: EgAABgIOMBgg
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: EwAAEwqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: FAAACQqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: FQAAIAqVQrTw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: FgAAeAWPSIDw
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: FwAAAw33Zb9Q
> Next fzzy: F7dtxwqVQ_Pw
> Fzzy: F7dt8QWPSIDw
>
> It's obvious that my FuzzyRowFilter knows what to search and every time it
> repeats its question.
> The very first key - I suppose is just the first key of a region where my
> key is located.
> The very last key - is the key that is already bigger than what I'm trying
> to find - that's the reason why FuzzyFilter stopped there.
>
> Do you know any issue with SEEK_NEXT_USING_HINT? I've searched, but
> unsuccessfully.
> Do you have any idea how to explain these many trials?
>
> Thanks in advance.
> --
> Evgeny Morozov
> Developer Grid Dynamics
> Skype: morozov.evgeny
> www.griddynamics.com
> [EMAIL PROTECTED]
>