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HBase >> mail # user >> Essential column family performance


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Re: Essential column family performance
bq. through multiple scans along the region boundaries
Sorry am not able to get what you are saying. Could you elaborate on this?
 I think the validity of this essential CF feature is best tested in real
use cases as that in Phoenix.

Regards
Ram
On Mon, Apr 8, 2013 at 11:12 PM, Ted Yu <[EMAIL PROTECTED]> wrote:

> bq. is the 40% randomly distributed or sequential?
> Looks like the distribution is striped:
>
>         if (i % 100 <= flag_percent) {
>
>           put.add(cf_essential, col_name, flag_yes);
> In each stripe, it is sequential.
>
> Let me try simulating random distribution.
>
> On Mon, Apr 8, 2013 at 10:38 AM, James Taylor <[EMAIL PROTECTED]
> >wrote:
>
> > In the TestJoinedScanners.java, is the 40% randomly distributed or
> > sequential?
> >
> > In our test, the % is randomly distributed. Also, our custom filter does
> > the same thing that SingleColumnValueFilter does.  On the client-side,
> we'd
> > execute the query in parallel, through multiple scans along the region
> > boundaries. Would that have a negative impact on performance for this
> > "essential column family" feature?
> >
> > Thanks,
> >
> >     James
> >
> >
> > On 04/08/2013 10:10 AM, Anoop John wrote:
> >
> >> Agree here. The effectiveness depends on what % of data satisfies the
> >> condition, how it is distributed across HFile blocks. We will get
> >> performance gain when the we will be able to skip some HFile blocks
> (from
> >> non essential CFs). Can test with different HFile block size (lower
> >> value)?
> >>
> >> -Anoop-
> >>
> >>
> >> On Mon, Apr 8, 2013 at 8:19 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
> >>
> >>  I made the following change in TestJoinedScanners.java:
> >>>
> >>> -      int flag_percent = 1;
> >>> +      int flag_percent = 40;
> >>>
> >>> The test took longer but still favors joined scanner.
> >>> I got some new results:
> >>>
> >>> 2013-04-08 07:46:06,959 INFO  [main] regionserver.**
> >>> TestJoinedScanners(157):
> >>> Slow scanner finished in 7.424388 seconds, got 2050 rows
> >>> ...
> >>> 2013-04-08 07:46:12,010 INFO  [main] regionserver.**
> >>> TestJoinedScanners(157):
> >>> Joined scanner finished in 5.05063 seconds, got 2050 rows
> >>>
> >>> 2013-04-08 07:46:18,358 INFO  [main] regionserver.**
> >>> TestJoinedScanners(157):
> >>> Slow scanner finished in 6.348517 seconds, got 2050 rows
> >>> ...
> >>> 2013-04-08 07:46:22,946 INFO  [main] regionserver.**
> >>> TestJoinedScanners(157):
> >>> Joined scanner finished in 4.587545 seconds, got 2050 rows
> >>>
> >>> Looks like effectiveness of joined scanner is affected by distribution
> of
> >>> data.
> >>>
> >>> Cheers
> >>>
> >>> On Sun, Apr 7, 2013 at 8:52 PM, lars hofhansl <[EMAIL PROTECTED]>
> wrote:
> >>>
> >>>  Looking at the joined scanner test code, it sets it up such that 1% of
> >>>>
> >>> the
> >>>
> >>>> rows match, which would somewhat be in line with James' results.
> >>>>
> >>>> In my own testing a while ago I found a 100% improvement with 0%
> match.
> >>>>
> >>>>
> >>>> -- Lars
> >>>>
> >>>>
> >>>>
> >>>> ______________________________**__
> >>>>   From: Ted Yu <[EMAIL PROTECTED]>
> >>>> To: [EMAIL PROTECTED]
> >>>> Sent: Sunday, April 7, 2013 4:13 PM
> >>>> Subject: Re: Essential column family performance
> >>>>
> >>>> I have attached 5416-TestJoinedScanners-0.94.**txt to HBASE-5416 for
> >>>> your
> >>>> reference.
> >>>>
> >>>> On my MacBook, I got the following results from the test:
> >>>>
> >>>> 2013-04-07 16:08:17,474 INFO  [main]
> >>>>
> >>> regionserver.**TestJoinedScanners(157):
> >>>
> >>>> Slow scanner finished in 7.973822 seconds, got 100 rows
> >>>> ...
> >>>> 2013-04-07 16:08:17,946 INFO  [main]
> >>>>
> >>> regionserver.**TestJoinedScanners(157):
> >>>
> >>>> Joined scanner finished in 0.47235 seconds, got 100 rows
> >>>>
> >>>> Cheers
> >>>>
> >>>> On Sun, Apr 7, 2013 at 4:03 PM, Ted Yu <[EMAIL PROTECTED]> wrote:
> >>>>
> >>>>  Looking at
> >>>>>
> >>>>>  https://issues.apache.org/**jira/secure/attachment/**
> >>> 12564340/5416-0.94-v3.txt<