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https://issues.apache.org/jira/browse/HBASE-6065?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13282091#comment-13282091
 ] 

Hudson commented on HBASE-6065:
-------------------------------

Integrated in HBase-TRUNK-on-Hadoop-2.0.0 #15 (See 
[https://builds.apache.org/job/HBase-TRUNK-on-Hadoop-2.0.0/15/])
    HBASE-6065 Log for flush would append a non-sequential edit in the hlog, 
leading to possible data loss (Chunhui) (Revision 1342019)

     Result = FAILURE
tedyu : 
Files : 
* 
/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogSplitter.java

                
> Log for flush would append a non-sequential edit in the hlog, leading to 
> possible data loss
> -------------------------------------------------------------------------------------------
>
>                 Key: HBASE-6065
>                 URL: https://issues.apache.org/jira/browse/HBASE-6065
>             Project: HBase
>          Issue Type: Bug
>          Components: wal
>            Reporter: chunhui shen
>            Assignee: chunhui shen
>            Priority: Critical
>             Fix For: 0.96.0, 0.94.1
>
>         Attachments: HBASE-6065.patch, HBASE-6065v2.patch
>
>
> After completing flush region, we will append a log edit in the hlog file 
> through HLog#completeCacheFlush.
> {code}
> public void completeCacheFlush(final byte [] encodedRegionName,
>       final byte [] tableName, final long logSeqId, final boolean 
> isMetaRegion)
> {
> ...
> HLogKey key = makeKey(encodedRegionName, tableName, logSeqId,
>             System.currentTimeMillis(), HConstants.DEFAULT_CLUSTER_ID);
> ...
> }
> {code}
> when we make the hlog key, we use the seqId from the parameter, and it is 
> generated by HLog#startCacheFlush,
> Here, we may append a lower seq id edit than the last edit in the hlog file.
> If it is the last edit log in the file, it may cause data loss.
> because 
> {code}
> HRegion#replayRecoveredEditsIfAny{
> ...
> maxSeqId = Math.abs(Long.parseLong(fileName));
>       if (maxSeqId <= minSeqId) {
>         String msg = "Maximum sequenceid for this log is " + maxSeqId
>             + " and minimum sequenceid for the region is " + minSeqId
>             + ", skipped the whole file, path=" + edits;
>         LOG.debug(msg);
>         continue;
>       }
> ...
> }
> {code}
> We may skip the splitted log file, because we use the lase edit's seq id as 
> its file name, and consider this seqId as the max seq id in this log file.

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