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HBase >> mail # user >> Understanding scan behaviour


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Mohit Anchlia 2013-03-28, 04:15
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Ted Yu 2013-03-28, 04:22
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ramkrishna vasudevan 2013-03-28, 04:23
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ramkrishna vasudevan 2013-03-28, 04:23
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Mohit Anchlia 2013-03-28, 14:38
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Jean-Marc Spaggiari 2013-03-28, 14:53
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Mohit Anchlia 2013-03-28, 15:17
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Jean-Marc Spaggiari 2013-03-28, 15:26
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Re: Understanding scan behaviour
I see then I misunderstood the behaviour. My keys are id + timestamp so
that I can do a range type search. So what I really want is to return a row
where id matches the prefix. Is there a way to do this without having to
scan large amounts of data?

On Thu, Mar 28, 2013 at 8:26 AM, Jean-Marc Spaggiari <
[EMAIL PROTECTED]> wrote:

> Hi Mohit,
>
> "+" ascii code is 43
> "9" ascii code is 57.
>
> So "+9" is coming after "++". If you don't have any row with the exact
> key "+++++", HBase will look for the first one after this one. And in
> your case, it's +9hC\xFC\x82s\xABL3\xB3B\xC0\xF9\x87\x03\x7F\xFF\xF.
>
> JM
>
> 2013/3/28 Mohit Anchlia <[EMAIL PROTECTED]>:
> > My understanding is that the row key would start with +++++ for instance.
> >
> > On Thu, Mar 28, 2013 at 7:53 AM, Jean-Marc Spaggiari <
> > [EMAIL PROTECTED]> wrote:
> >
> >> Hi Mohit,
> >>
> >> I see nothing wrong with the results below. What would I have expected?
> >>
> >> JM
> >>
> >> 2013/3/28 Mohit Anchlia <[EMAIL PROTECTED]>:
> >>  > I am running 92.1 version and this is what happens.
> >> >
> >> >
> >> > hbase(main):003:0> scan 'SESSIONID_TIMELINE', {LIMIT => 1, STARTROW =>
> >> > 'sdw0'}
> >> > ROW                                                  COLUMN+CELL
> >> >  s\xC1\xEAR\xDF\xEA&\x89\x91\xFF\x1A^\xB6d\xF0\xEC\x
> >> > column=SID_T_MTX:\x00\x00Rc, timestamp=1363056261106,
> >> > value=PAGE\x09\x091363056252990\x09\x09/
> >> >  7F\xFF\xFE\xC2\xA3\x84Z\x7F
> >> >
> >> > 1 row(s) in 0.0450 seconds
> >> > hbase(main):004:0> scan 'SESSIONID_TIMELINE', {LIMIT => 1, STARTROW =>
> >> > '------'}
> >> > ROW                                                  COLUMN+CELL
> >> >  -\xA1\xAF>r\xBD\xE2L\x00\xCD*\xD7\xE8\xD6\x1Dk\x7F\
> >> > column=SID_T_MTX:\x00\x00hF, timestamp=1363384706714,
> >> > value=PAGE\x09239923973\x091363384698919\x09/
> >> >  xFF\xFE\xC2\x8F\xF0\xC1\xBF
> >> >   row(s) in 0.0500 seconds
> >> > hbase(main):005:0> scan 'SESSIONID_TIMELINE', {LIMIT => 1, STARTROW =>
> >> > '++++'}
> >> > ROW                                                  COLUMN+CELL
> >> >  +9hC\xFC\x82s\xABL3\xB3B\xC0\xF9\x87\x03\x7F\xFF\xF
> >> > column=SID_T_MTX:\x00\x00<2, timestamp=1364404155426,
> >> > value=PAGE\x09\x091364404145275\x09 \x09/
> >> >  E\xC2S-\x08\x1F
> >> > 1 row(s) in 0.0640 seconds
> >> > hbase(main):006:0>
> >> >
> >> >
> >> > On Wed, Mar 27, 2013 at 9:23 PM, ramkrishna vasudevan <
> >> > [EMAIL PROTECTED]> wrote:
> >> >
> >> >> Same question, same time :)
> >> >>
> >> >> Regards
> >> >> Ram
> >> >>
> >> >> On Thu, Mar 28, 2013 at 9:53 AM, ramkrishna vasudevan <
> >> >> [EMAIL PROTECTED]> wrote:
> >> >>
> >> >> > Could you give us some more insights on this?
> >> >> > So you mean when you set the row key as 'azzzaaa', though this row
> >> does
> >> >> > not exist, the scanner returns some other row?  Or it is giving
> you a
> >> row
> >> >> > that does not exist?
> >> >> >
> >> >> > Or you mean it is doing a full table scan?
> >> >> >
> >> >> > Which version of HBase and what type of filters are you using?
> >> >> > Regards
> >> >> > Ram
> >> >> >
> >> >> >
> >> >> > On Thu, Mar 28, 2013 at 9:45 AM, Mohit Anchlia <
> >> [EMAIL PROTECTED]
> >> >> >wrote:
> >> >> >
> >> >> >> I have key in the form of "hashedid + timestamp" but when I run
> scan
> >> I
> >> >> get
> >> >> >> rows for almost every value. For instance if I run scan for
> 'azzzaaa'
> >> >> that
> >> >> >> doesn't even exist even then I get the results.
> >> >> >>
> >> >> >> Could someone help me understand what might be going on here?
> >> >> >>
> >> >> >
> >> >> >
> >> >>
> >>
>
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Ted Yu 2013-03-28, 16:15
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Mohit Anchlia 2013-03-28, 17:17
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Ted Yu 2013-03-28, 17:23
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Li, Min 2013-03-29, 05:48
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ramkrishna vasudevan 2013-03-29, 06:20
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James Taylor 2013-03-29, 07:44
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Mohit Anchlia 2013-03-29, 16:31
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Asaf Mesika 2013-03-30, 13:55
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Mohit Anchlia 2013-03-30, 15:25
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Ted Yu 2013-03-30, 16:37