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Date: Thu, 15 Nov 2012 05:40:12 +0000 (UTC)
From: "Ted Yu (JIRA)" <jira@apache.org>
To: issues@hbase.apache.org
Message-ID: <1219968050.117796.1352958012618.JavaMail.jiratomcat@arcas>
In-Reply-To: <764868728.63748.1351902251865.JavaMail.jiratomcat@arcas>
Subject: [jira] [Commented] (HBASE-7093) Couple Increments/Appends with
 Put/Delete(s)
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    [ https://issues.apache.org/jira/browse/HBASE-7093?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13497778#comment-13497778 ] 

Ted Yu commented on HBASE-7093:
-------------------------------

In javadoc, describe what the method does:
{code}
+  boolean prepareAppend(Append append, long now, boolean advanceMemstoreRead) throws IOException {
{code}
Also, add @return javadoc.
{code}
+    boolean advancedMemstoreRead = false;
+    if (advanceMemstoreRead) {
{code}
Why introducing a local variable which is spelled almost exactly the same as method parameter ?
Looking at the method's return value, it would be the same as that of the input parameter, advanceMemstoreRead. Looks like you don't need advancedMemstoreRead.
{code}
+        advancedMemstoreWrite = region.prepareAppend((Append)m, now, !advancedMemstoreWrite);
{code}
Can you explain the role for advancedMemstoreWrite above (especially the assignment) ?
                
> Couple Increments/Appends with Put/Delete(s)
> --------------------------------------------
>
>                 Key: HBASE-7093
>                 URL: https://issues.apache.org/jira/browse/HBASE-7093
>             Project: HBase
>          Issue Type: Improvement
>    Affects Versions: 0.96.0
>            Reporter: Varun Sharma
>            Assignee: Varun Sharma
>         Attachments: 7093-v1.txt
>
>
> See related issue - https://issues.apache.org/jira/browse/HBASE-4583
> Currently, we cannot bundle increment/append with put/delete operations. The above JIRA MVCC'izes the increment/append operations.
> One issue is that increment(s)/append(s) are not idempotent and hence repeating the transaction has an associated issue of leading to incorrect value/append results. This could be solved by passing additional tokens as part of the append(s).
> One possible high level approach could be:
> 1) Class IncrementMutation which inherits from Increment and Mutation
> 2) In the mutateRow call, we add a case for "IncrementMutation" object
> 3) Factor out the code wrapped inside the "lock and MVCC" from increment() function to internalIncrement.
> 4) Call internalIncrement from mutateRow and increment()

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