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HBase >> mail # user >> paging results filter


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Toby Lazar 2013-01-24, 12:50
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Mohammad Tariq 2013-01-24, 12:52
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Toby Lazar 2013-01-24, 13:14
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Anoop Sam John 2013-01-25, 03:34
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ramkrishna vasudevan 2013-01-25, 04:15
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Mohammad Tariq 2013-01-25, 05:15
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Re: paging results filter
Yes, I think so.  I thought that reading random pages of results without
knowing the starting row seems like a pretty common use case (looks like
Vijay asked about a similar use case yesterday) and wondered if it is
already included in the OOTB hbase filters.  What I understood from the
discussion is that PageFilter does not provide this functionality and that
I indeed do need a custom filter to achieve that (efficiently).

Thank you all for your responses.

Toby

On Fri, Jan 25, 2013 at 12:15 AM, Mohammad Tariq <[EMAIL PROTECTED]> wrote:

> Hello Toby,
>
>       Sorry for the late reply. But, you have got appropriate answers from
> the pros :)
>
> Warm Regards,
> Tariq
> https://mtariq.jux.com/
> cloudfront.blogspot.com
>
>
> On Fri, Jan 25, 2013 at 9:45 AM, ramkrishna vasudevan <
> [EMAIL PROTECTED]> wrote:
>
> > @Toby
> >
> > If you wish to go the specified page you need to set the start row that
> > needs to come as part of that page.
> > So what i feel is implement a custom page filter and keep doing next()
> and
> > display only those records that suits the page you clicked.
> >  and send them back to the client.  Anyway the logic inside the filter
> > should keep track of the number of records that passed by till you reach
> > your concerned page and that should
> > be  based on the number of records on a page.
> >
> > Regards
> > Ram
> >
> > On Fri, Jan 25, 2013 at 9:04 AM, Anoop Sam John <[EMAIL PROTECTED]>
> > wrote:
> >
> > > @Toby
> > >
> > > You mean to say that you need a mechanism for directly jumping to a
> page.
> > > Say you are in page#1 (1-20) now and you want to jump to
> page#4(61-80)..
> > > Yes this is not there in PageFilter...
> > > The normal way of next page , next page will work fine as within the
> > > server the next() calls on the scanner works this way...
> > >
> > > -Anoop-
> > > ________________________________________
> > > From: Toby Lazar [[EMAIL PROTECTED]]
> > > Sent: Thursday, January 24, 2013 6:44 PM
> > > To: [EMAIL PROTECTED]
> > > Subject: Re: paging results filter
> > >
> > > I don't see a way of specifying which page of resluts I want.  For
> > example,
> > > if I want page 3 with page size of 20 (only results 41-60), I don't see
> > how
> > > PageFilter can be configued for that.  Am I missing the obvious?
> > >
> > > Thanks,
> > >
> > > Toby
> > >
> > > On Thu, Jan 24, 2013 at 7:52 AM, Mohammad Tariq <[EMAIL PROTECTED]>
> > > wrote:
> > >
> > > > I think you need
> > > > PageFilter<
> > > >
> > >
> >
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/filter/PageFilter.html
> > > > >
> > > > .
> > > >
> > > > HTH
> > > >
> > > > Warm Regards,
> > > > Tariq
> > > > https://mtariq.jux.com/
> > > > cloudfront.blogspot.com
> > > >
> > > >
> > > > On Thu, Jan 24, 2013 at 6:20 PM, Toby Lazar <[EMAIL PROTECTED]>
> wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > I need to create a client function that allows paging of scan
> results
> > > > > (initially return results 1-20, then click on page to to show
> results
> > > > > 21-40, 41-60, etc.) without needing to remember the start rowkey.
>  I
> > > > > beleive that a filter would be far more efficient than implementing
> > the
> > > > > logic client-side.  I couldn't find any OOTB filter for this
> > > > functionality
> > > > > so I wrote the class below.  It seems to work fine for me, but can
> > > anyone
> > > > > comment if this approach makes sense?  Is there another OOTB filter
> > > that
> > > > I
> > > > > can use instead?
> > > > >
> > > > > Thank you,
> > > > >
> > > > > Toby
> > > > >
> > > > >
> > > > >
> > > > > import java.io.DataInput;
> > > > > import java.io.DataOutput;
> > > > > import java.io.IOException;
> > > > > import org.apache.hadoop.hbase.filter.FilterBase;
> > > > > public class PageOffsetFilter extends FilterBase {
> > > > >  private long startRowCount;
> > > > >  private long endRowCount;
> > > > >
> > > > >  private int count = 0;
> > > > >  public PageOffsetFilter() {
> > > > >  }
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB