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From "Sylvain Lebresne (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-7403) Reconciliation doesn't consider fields specific to expiring cells
Date Mon, 07 Jul 2014 14:02:34 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-7403?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14053672#comment-14053672
] 

Sylvain Lebresne commented on CASSANDRA-7403:
---------------------------------------------

To be clear, I don't feel strongly on whether we should favour values-over-ttl or ttl-over-values
in theory, I don't think it matters much on paper. But that's why I prefer keeping the existing
behaviour.

> Reconciliation doesn't consider fields specific to expiring cells 
> ------------------------------------------------------------------
>
>                 Key: CASSANDRA-7403
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7403
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Sam Tunnicliffe
>            Assignee: Benedict
>             Fix For: 2.1.0
>
>
> Reconciling 2 ExpiringColumns which are equal in every way except for the localExpirationTime
field will always favour the instance on which reconcile is called as fields specific to expiration
are not considered. 
> This is actually beneficial in pre-2.1 versions as in AtomicSortedColumns.Holder.addColumn
we call reconcile on the new column, which 'wins' the reconcilliation and so the localExpirationTime
is effectively extended.
> From 2.1 onwards, reconcile is actually called on the existing value (in BTreeSortedColumns.ColumnUpdater)
and so it wins the reconcilliation and the ttl doesn't get extended. The same thing happens
in the iterator returned from MergeIterator.Reducer.getReducer() so we see the same behaviour
when merging cells from the multiple SSTables and/or memtables.



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