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From lars hofhansl <lhofha...@yahoo.com>
Subject Re: RS unresponsive after series of deletes
Date Sat, 23 Jun 2012 02:35:12 GMT
Sorry for chiming in late.

Are you sure you want to use Delete.deleteColumn and not Delete.deleteColumns (note the plural
deleteColumn marks a single version of a column (of a CF of a Row) for deletion
deleteColumns marks all versions of a column as deleted (unless you specify a timestamp).

deleteColumns is what you want in most cases unless you carefully have to control individual
version of a specific column in a specific row.

-- Lars

 From: Ted Tuttle <ted.tuttle@mentacapital.com>
To: user@hbase.apache.org 
Cc: Development <Development@mentacapital.com> 
Sent: Thursday, June 21, 2012 7:02 AM
Subject: RE: RS unresponsive after series of deletes
Good hint, Ted

By calling Delete.deleteColumn(family, qual, ts) instead of deleteColumn
w/o timestamp, the time to delete row keys is reduced by 95%.

I am going to experiment w/ limited batches of Deletes, too.

Thanks everyone for help on this one.

-----Original Message-----
From: Ted Yu [mailto:yuzhihong@gmail.com] 
Sent: Wednesday, June 20, 2012 10:13 PM
To: user@hbase.apache.org
Subject: Re: RS unresponsive after series of deletes

As I mentioned earlier, prepareDeleteTimestamps() performs one get
operation per column qualifier:
          get.addColumn(family, qual);

          List<KeyValue> result = get(get, false);
This is too costly in your case.
I think you can group some configurable number of qualifiers in each get
and perform classification on result.
This way we can reduce the number of times
is called.


On Wed, Jun 20, 2012 at 9:54 PM, Ted Tuttle

> > Do your 100s of thousands cell deletes overlap (in terms of column
> family)
> > across rows ?
> Our schema contains only one column family per table. So, each Delete
> contains cells from a single column family.  I hope this answers your
> question.
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