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Re: Understanding scan behaviour
Thanks everyone, it's really helpful. I'll change my prefix filter to end
row. Is it necessary to increment the last byte? So if I have hash of
1234555 my end key should be 1234556?
On Thu, Mar 28, 2013 at 11:20 PM, ramkrishna vasudevan <
[EMAIL PROTECTED]> wrote:

> Mohith,
>
> It is always better to go with start row and end row if you are knowing
> what are they.
> Just add one byte more to the actual end row (inclusive row) and form the
> end key.  This will narrow down the search.
>
> Remeber the byte comparison is the way that HBase scans.
> Regards
> Ram
>
> On Fri, Mar 29, 2013 at 11:18 AM, Li, Min <[EMAIL PROTECTED]> wrote:
>
> > Hi, Mohit,
> >
> > Try using ENDROW. STARTROW&ENDROW is much faster than PrefixFilter.
> >
> > "+" ascii code is 43
> > "," ascii code is 44
> >
> > scan 'SESSIONID_TIMELINE', {LIMIT => 1,STARTROW => '++++',
> ENDROW=>'+++,'}
> >
> > Min
> >
> > -----Original Message-----
> > From: Mohit Anchlia [mailto:[EMAIL PROTECTED]]
> > Sent: Friday, March 29, 2013 1:18 AM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Understanding scan behaviour
> >
> > Could the prefix filter lead to full tablescan? In other words is
> > PrefixFilter applied after fetching the rows?
> >
> > Another question I have is say I have row key abc and abd and I search
> for
> > row "abc", is it always guranteed to be the first key when returned from
> > scanned results? If so I can alway put a condition in the client app.
> >
> > On Thu, Mar 28, 2013 at 9:15 AM, Ted Yu <[EMAIL PROTECTED]> wrote:
> >
> > > Take a look at the following in
> > > hbase-server/src/main/ruby/shell/commands/scan.rb
> > > (trunk)
> > >
> > >   hbase> scan 't1', {FILTER => "(PrefixFilter ('row2') AND
> > >     (QualifierFilter (>=, 'binary:xyz'))) AND (TimestampsFilter ( 123,
> > > 456))"}
> > >
> > > Cheers
> > >
> > > On Thu, Mar 28, 2013 at 9:02 AM, Mohit Anchlia <[EMAIL PROTECTED]
> > > >wrote:
> > >
> > > > 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\