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From aaron morton <>
Subject Re: will compaction delete empty rows after all columns expired?
Date Wed, 30 May 2012 22:57:53 GMT
Minor compaction will remove the tombstones if the row only exists in the sstable being compaction.

Are these very wide rows that are constantly written to ? 

 p.s. cassandra 1.0 really does rock. 

Aaron Morton
Freelance Developer

On 26/05/2012, at 6:21 AM, Curt Allred wrote:

> This is an old thread from December 27, 2011.  I interpret the "yes" answer to mean you
do not have to explicitly delete an empty row after all of its columns have been deleted,
the empty row (i.e. row key) will automatically be deleted eventually (after gc_grace).  Is
that true?   I am not seeing that behavior on our v 0.7.9 ring.  We are accumulating a large
number of old empty rows.  They are taking alot of space because the row keys are big, and
exploding the data size by 10x.  I have read conflicting information on blogs and cassandra
docs.  Someone mentioned that there are both row tombstones and column tombstones, implying
that you have to explicitly delete empty rows.  Is that correct.
> My basic question is... how do I delete all these empty row keys?
> -----------------------------
> From: Feng Qu
> Sent: Tuesday, December 27, 2011 11:09 AM
> Compaction should delete empty rows once gc_grace_seconds is passed, right? 
> -----------------------------
> From: Peter Schuller
> Yes.  
> But just to be extra clear: Data will not actually be removed once the row in question
participates in compaction. Compactions will not be actively triggered by Cassandra for tombstone
processing reasons.

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