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https://issues.apache.org/jira/browse/CASSANDRA-10547?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15004408#comment-15004408
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Jim Witschey commented on CASSANDRA-10547:
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[~sperkins] Thanks for chiming in. A few questions:

- What version of C* are you using?
- About how many values are in the lists? (or do you mean some other collection 
when you say "array"?)
- About how many tombstones are created on updates?

And just to confirm: it sounds like the kinds of operations you're doing are 
{{UPDATE}}s on a small subset of the items in a list?

> Updating a CQL List many times creates many tombstones 
> -------------------------------------------------------
>
>                 Key: CASSANDRA-10547
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10547
>             Project: Cassandra
>          Issue Type: Bug
>         Environment: Cassandra 2.1.9, Java driver 2.1.5
>            Reporter: James Bishop
>         Attachments: tombstone.snippet
>
>
> We encountered a TombstoneOverwhelmingException in cassandra system.log which 
> caused some of our CQL queries to fail.
> We are able to reproduce this issue by updating a CQL List column many times. 
> The number of tombstones created seems to be related to (number of list items 
> * number of list updates). We update the entire list on each update using the 
> java driver. (see attached code for details)
> Running nodetool compact does not help, but nodetool flush does. It appears 
> that the tombstones are being accumulated in memory. 
> For example if we update a list of 100 items 1000 times, this creates more  
> than 100,000 tombstones and exceeds the default tombstone_failure_threshold.



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