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From aaron morton <aa...@thelastpickle.com>
Subject Re: Strange delay in query
Date Tue, 13 Nov 2012 08:54:04 GMT
> I don't think that statement is accurate.
Which part ?

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 13/11/2012, at 6:31 AM, Binh Nguyen <binhnv80@gmail.com> wrote:

> I don't think that statement is accurate. The minor compaction is still triggered for
small sstables but for the big sstables it may or may not.
> By default Cassandra will wait until it finds 4 sstables of the same size to trigger
the compaction so if the sstables are big then it may take a while to be compacted.
> If you are sure that you have a lot of tombstones and they will be deleted then I think
you are safe to go.
> 
> -Binh
> 
> On Sun, Nov 11, 2012 at 1:51 AM, André Cruz <andre.cruz@co.sapo.pt> wrote:
> On Nov 11, 2012, at 12:01 AM, Binh Nguyen <binhnv80@gmail.com> wrote:
> 
>> FYI: Repair does not remove tombstones. To remove tombstones you need to run compaction.
>> If you have a lot of data then make sure you run compaction on all nodes before running
repair. We had a big trouble with our system regarding tombstone and it took us long time
to figure out the reason. It turned out that repair process also transfers TTLed data (compaction
is not triggered yet) to the other nodes even that data was removed from the other nodes in
the compaction phase before that.
>> 
> 
> Aren't compactions triggered automatically? At least minor compactions. Also, I read
this in http://www.datastax.com/docs/1.1/operations/tuning#tuning-compaction :
> 
> " After running a major compaction, automatic minor compactions are no longer triggered,
frequently requiring you to manually run major compactions on a routine basis."
> "DataStax does not recommend major compaction."
> 
> So I'm unsure whether to start triggering manually these compactions… I guess I'll
have to experiment with it.
> 
> Thanks!
> 
> André
> 


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