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From "Modha, Digant" <Digant.Mo...@tdsecurities.com>
Subject RE: Delete By Partition Key Implementation
Date Thu, 21 Aug 2014 18:44:52 GMT
If you delete entire row, do the records in the row still get counted towards computing TombstoneOverwhelmingException?
 It seems like they still do.

From: DuyHai Doan [mailto:doanduyhai@gmail.com]
Sent: Saturday, August 09, 2014 3:21 AM
To: user@cassandra.apache.org
Subject: Re: Delete By Partition Key Implementation


Thanks graham for the hints.

I've digged into the source code and found out those 2 classes:

https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/db/DeletionInfo.java

https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/db/RangeTombstoneList.java

 They are quite self-explanatory.
A deletion of an entire row is a single row tombstone, and yes there are range tombstones
for marking deletion of a range of columns also

On Aug 8, 2014, at 2:17 PM, Kevin Burton <burton@spinn3r.com<mailto:burton@spinn3r.com>>
wrote:


This is a good question.. I'd love to find out the answer.  Seems like a tombstone with prefixes
for the keys would work well.

Also, can't any key prefixes work in theory?

On Thu, Aug 7, 2014 at 8:33 AM, DuyHai Doan <doanduyhai@gmail.com<mailto:doanduyhai@gmail.com>>
wrote:
Hello all

 Usually, when using DELETE in CQL3 on some fields, C* creates tombstone columns for those
fields.

 Now if I delete a whole PARTITION (delete from MyTable where partitionKey=...), what will
C* do ? Will it create as many tombstones as there are physical columns on this partition
or will it just mark this partition as "deleted" (Row Key deletion marker) ?

 On a side note, if I insert a bunch of physical columns in one partition with the SAME ttl
value, after a while they will appear as expired, would C* need to scan the whole partition
on disk to see which columns to expire or could it see that the whole partition is indeed
expired thanks to meta data/ Partition key cache kept in memory ?  I was thinking about the
estimate histograms for TTL but I don't know in detail how it work

 Regards

 Duy Hai  DOAN




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