cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Sam Tunnicliffe (JIRA)" <j...@apache.org>
Subject [jira] [Issue Comment Edited] (CASSANDRA-4116) check most recent TS values in SSTables when a row tombstone has already been encountered
Date Tue, 01 May 2012 16:13:50 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-4116?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13265881#comment-13265881
] 

Sam Tunnicliffe edited comment on CASSANDRA-4116 at 5/1/12 4:12 PM:
--------------------------------------------------------------------

Updated patches as per comments. In {{collectAllData}}, collect the eligible iterators in
a multimap with key = maxTimestamp (I guess that its pretty unlikely for two sstables to have
the exact same timestamp, but using a Multimap doesn't really add any cost). Then, if we did
find a row tombstone, only keep the iterators from younger sstables. Otherwise, keep all that
we collected.
                
      was (Author: beobal):
    Updated patches as per comments. In {code}collectAllData{code}, collect the eligible iterators
in a multimap with key = maxTimestamp (I guess that its pretty unlikely for two sstables to
have the exact same timestamp, but using a Multimap doesn't really add any cost). Then, if
we did find a row tombstone, only keep the iterators from younger sstables. Otherwise, keep
all that we collected.
                  
> check most recent TS values in SSTables when a row tombstone has already been encountered
> -----------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-4116
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4116
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Matthew F. Dennis
>            Assignee: Sam Tunnicliffe
>             Fix For: 1.2
>
>         Attachments: v1-0001-CASSANDRA-4116-After-Row-tombstone-skip-earlier-SSTabl.txt,
v1-0002-CASSANDRA-4116-Set-SSTable-maxTimestamp-correctly-for-.txt
>
>
> once C* comes across a row tombstone, C* should check the TS on the tombstone against
all SSTables.  If the most recent TS in an SST is older than the row tombstone, that entire
SST (or the remainder of it) can be safely ignored.
> There are two drivers for this.
> * avoid checking column values that could not possibly be in the result set
> * avoid OOMing because all the tombstones are temporarily kept in memory.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message