[jira] [Commented] (CASSANDRA-4667) optimize memtable deletions for batchlog

["Aleksey Yeschenko (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-4667?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13456525#comment-13456525 ] 

Aleksey Yeschenko commented on CASSANDRA-4667:
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Why can't we do something similar to [removeDeletedColumnsOnly() call in writeSortedContents()] when inserting cfs with cf.isMarkedForDelete() == true into a memtable in general case? Why not move this optimization from memtable flush to memtable insert? This will require changing resolve code, but probably worth it. Am I missing something?
                
> optimize memtable deletions for batchlog
> ----------------------------------------
>
>                 Key: CASSANDRA-4667
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4667
>             Project: Cassandra
>          Issue Type: Sub-task
>            Reporter: Aleksey Yeschenko
>            Assignee: Aleksey Yeschenko
>         Attachments: CASSANDRA-4667-v1.1.patch, CASSANDRA-4667-v2.patch
>
>
> Batchlog writes with the same key are never retried. This means that if a batchlog row is in the memtable, it can't be in any of the sstables, ever. In such cases we don't need to write a tombstone to disk. We can purge the row completely from the memtable and only write a tombstone if the row had been flushed already (if it's not in the memtable then it must be in one of the sstables).

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