hbase-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From jeremy p <athomewithagroove...@gmail.com>
Subject Re: How to do a fast range scan on a prefix
Date Fri, 05 Jun 2015 19:21:05 GMT
Excellent.  This is exactly what I need.  Thank you!

On Fri, Jun 5, 2015 at 3:07 PM, Ted Yu <yuzhihong@gmail.com> wrote:

> Clarification: setRowPrefixFilter() doesn't use PrefixFilter. It calculates
> the scan range itself:
>
>   public Scan setRowPrefixFilter(byte[] rowPrefix) {
>
>     if (rowPrefix == null) {
>
>       setStartRow(HConstants.EMPTY_START_ROW);
>
>       setStopRow(HConstants.EMPTY_END_ROW);
>
>     } else {
>
>       this.setStartRow(rowPrefix);
>
>       this.setStopRow(calculateTheClosestNextRowKeyForPrefix(rowPrefix));
>
>     }
>
> FYI
>
> On Fri, Jun 5, 2015 at 11:27 AM, jeremy p <athomewithagroovebox@gmail.com>
> wrote:
>
> > I've heard that PrefixFilter does a full table scan, and that a range
> scan
> > is faster.  Am I mistaken?
> >
> > On Fri, Jun 5, 2015 at 2:22 PM, Ted Yu <yuzhihong@gmail.com> wrote:
> >
> > > You can utilize PrefixFilter.
> > >
> > > See example in http://hbase.apache.org/book.html#scan
> > >
> > > On Fri, Jun 5, 2015 at 11:18 AM, jeremy p <
> > athomewithagroovebox@gmail.com>
> > > wrote:
> > >
> > > > Assume that my keys look like this :
> > > > bar:0
> > > > bar:1
> > > > bar:2
> > > > baz:0
> > > > baz:1
> > > > foo:0
> > > > foo:1
> > > > foo:2
> > > >
> > > > How do I do a fast range scan that returns all the rows that begin
> with
> > > > "baz:"?  Assume that I know nothing about any of the other rows in
> the
> > > > table.
> > > >
> > > > Thanks for taking a look!
> > > >
> > > > --Jeremy
> > > >
> > >
> >
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message