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Date: Thu, 12 Apr 2012 18:51:18 +0000 (UTC)
From: "Lars Hofhansl (Commented) (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
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Subject: [jira] [Commented] (HBASE-3443) ICV optimization to look in
 memstore first and then store files (HBASE-3082) does not work when deletes
 are in the mix
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    [ https://issues.apache.org/jira/browse/HBASE-3443?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13252726#comment-13252726 ] 

Lars Hofhansl commented on HBASE-3443:
--------------------------------------

@Stack: Wasn't sure about this one. Didn't feel right to add this to a "performance release" :)

You think this should go into 0.94? Might be good to have this correctness fix early.
                
> ICV optimization to look in memstore first and then store files (HBASE-3082) does not work when deletes are in the mix
> ----------------------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-3443
>                 URL: https://issues.apache.org/jira/browse/HBASE-3443
>             Project: HBase
>          Issue Type: Bug
>          Components: regionserver
>    Affects Versions: 0.90.0, 0.90.1, 0.90.2, 0.90.3, 0.90.4, 0.90.5, 0.90.6, 0.92.0, 0.92.1
>            Reporter: Kannan Muthukkaruppan
>            Assignee: Lars Hofhansl
>            Priority: Critical
>              Labels: corruption
>             Fix For: 0.96.0
>
>         Attachments: 3443.txt
>
>
> For incrementColumnValue() HBASE-3082 adds an optimization to check memstores first, and only if not present in the memstore then check the store files. In the presence of deletes, the above optimization is not reliable.
> If the column is marked as deleted in the memstore, one should not look further into the store files. But currently, the code does so.
> Sample test code outline:
> {code}
> admin.createTable(desc)
> table = HTable.new(conf, tableName)
> table.incrementColumnValue(Bytes.toBytes("row"), cf1name, Bytes.toBytes("column"), 5);
> admin.flush(tableName)
> sleep(2)
> del = Delete.new(Bytes.toBytes("row"))
> table.delete(del)
> table.incrementColumnValue(Bytes.toBytes("row"), cf1name, Bytes.toBytes("column"), 5);
> get = Get.new(Bytes.toBytes("row"))
> keyValues = table.get(get).raw()
> keyValues.each do |keyValue|
>   puts "Expect 5; Got Value=#{Bytes.toLong(keyValue.getValue())}";
> end
> {code}
> The above prints:
> {code}
> Expect 5; Got Value=10
> {code}

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