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Posted to user@hbase.apache.org by Whitney Sorenson <ws...@hubspot.com> on 2012/05/30 18:37:21 UTC
HBase to MapReduce Scans missing rows
We have been using HBase Scans to feed MapReduce jobs for over a year
now. However, on close inspection, we have seen instances where some
block of rows are inexplicably missing.
We thought that this may happen during region splits or with jobs with
many mappers, but we have seen, for example, 1000 rows missing from a
150,000 row scan coming from a single mapper.
It is not easily reproducible - launching the job again includes all
the rows. Does anyone have any insight into what may be going on, or
if there is a bug somewhere?
Thank you.
Re: HBase to MapReduce Scans missing rows
Posted by Stack <st...@duboce.net>.
On Wed, May 30, 2012 at 10:45 AM, Whitney Sorenson
<ws...@hubspot.com> wrote:
> HBase Version 0.90.4-cdh3u2, r HBase version and svn revision
> HBase Compiled Thu Oct 13 20:32:26 PDT 2011, jenkins When HBase
> version was compiled and by whom
> Hadoop Version 0.20.2-cdh3u2,
> r95a824e4005b2a94fe1c11f1ef9db4c672ba43cb Hadoop version and svn
> revision
> Hadoop Compiled Thu Oct 13 21:51:41 PDT 2011, root
>
There was this thread w/ some suggestions on where to look:
http://search-hadoop.com/m/hMHbv1OfyUf/hbase+missing+rows&subj=HBase+0+90+4+missing+data+in+production
IIRC Cosmin had similar issue and upgrade to 0.92.1 fixed it. He
thought it was lack of proper atomicity in 0.90.4.
St.Ack
Re: HBase to MapReduce Scans missing rows
Posted by Whitney Sorenson <ws...@hubspot.com>.
HBase Version 0.90.4-cdh3u2, r HBase version and svn revision
HBase Compiled Thu Oct 13 20:32:26 PDT 2011, jenkins When HBase
version was compiled and by whom
Hadoop Version 0.20.2-cdh3u2,
r95a824e4005b2a94fe1c11f1ef9db4c672ba43cb Hadoop version and svn
revision
Hadoop Compiled Thu Oct 13 21:51:41 PDT 2011, root
On Wed, May 30, 2012 at 1:44 PM, Stack <st...@duboce.net> wrote:
> On Wed, May 30, 2012 at 9:37 AM, Whitney Sorenson <ws...@hubspot.com> wrote:
>> We have been using HBase Scans to feed MapReduce jobs for over a year
>> now. However, on close inspection, we have seen instances where some
>> block of rows are inexplicably missing.
>>
>> We thought that this may happen during region splits or with jobs with
>> many mappers, but we have seen, for example, 1000 rows missing from a
>> 150,000 row scan coming from a single mapper.
>>
>> It is not easily reproducible - launching the job again includes all
>> the rows. Does anyone have any insight into what may be going on, or
>> if there is a bug somewhere?
>>
>
> Which version of HBase Whitney?
> St.Ack
Re: HBase to MapReduce Scans missing rows
Posted by Stack <st...@duboce.net>.
On Wed, May 30, 2012 at 9:37 AM, Whitney Sorenson <ws...@hubspot.com> wrote:
> We have been using HBase Scans to feed MapReduce jobs for over a year
> now. However, on close inspection, we have seen instances where some
> block of rows are inexplicably missing.
>
> We thought that this may happen during region splits or with jobs with
> many mappers, but we have seen, for example, 1000 rows missing from a
> 150,000 row scan coming from a single mapper.
>
> It is not easily reproducible - launching the job again includes all
> the rows. Does anyone have any insight into what may be going on, or
> if there is a bug somewhere?
>
Which version of HBase Whitney?
St.Ack