incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Ken Hancock <ken.hanc...@schange.com>
Subject Re: Update SSTable fragmentation
Date Wed, 09 Apr 2014 20:48:48 GMT
I don't believe so.  Cassandra still needs to hit the bloom filters for
each SST table and then reconcile all versions and all tombstones for any
row.  That's why overwrites have similar performance impact as tombstones,
overwrites just happen to be less common.



On Wed, Apr 9, 2014 at 2:42 PM, Wayne Schroeder <
wschroeder@pinsightmedia.com> wrote:

> I've been doing a lot of reading on SSTable fragmentation due to updates
> and the costs associated with reconstructing the end data from multiple
> SSTables that have been created over time and not yet compacted.  One
> question is stuck in my head: If you re-insert entire rows instead of
> updating one column, will cassandra end flushing that entire row into one
> SSTable on disk and then end up up finding a non fragmented entire row
> quickly on reads instead of potential reconstruction across multiple
> SSTables?  Obviously this has implications for space as a trade off.
>
> Wayne
>
>


-- 
*Ken Hancock *| System Architect, Advanced Advertising
SeaChange International
50 Nagog Park
Acton, Massachusetts 01720
ken.hancock@schange.com | www.schange.com |
NASDAQ:SEAC<http://www.schange.com/en-US/Company/InvestorRelations.aspx>

Office: +1 (978) 889-3329 | [image: Google Talk:]
ken.hancock@schange.com | [image:
Skype:]hancockks | [image: Yahoo IM:]hancockks [image:
LinkedIn]<http://www.linkedin.com/in/kenhancock>

[image: SeaChange International]
 <http://www.schange.com/>This e-mail and any attachments may contain
information which is SeaChange International confidential. The information
enclosed is intended only for the addressees herein and may not be copied
or forwarded without permission from SeaChange International.

Mime
View raw message