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https://issues.apache.org/jira/browse/HBASE-2643?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12897697#action_12897697
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Richard Lackey commented on HBASE-2643:
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There is an assumption that no RuntimeException will occur within splitLog.
While such an exception is remote, it is possible. Should a RuntimeException
occur, then it will percolate through HMaster, which will not join the cluster.
This is a general condition. The assumption in HDFS is that this cannot occur
(or will be caught by upper layer), which is to say that none of the lower
layers catches Exception to prevent the RuntimeException, e.g.,
NullPointerException, from percolating through. If the SequenceFile contains
garbage (or has been corrupted), then the opportunity for the underlying
DataInputStream to throw a RuntimeException increases.
The solution is to add a catch for Exception in splitLog and consider the log
corrupt.
> Figure how to deal with eof splitting logs
> ------------------------------------------
>
> Key: HBASE-2643
> URL: https://issues.apache.org/jira/browse/HBASE-2643
> Project: HBase
> Issue Type: Bug
> Reporter: stack
> Priority: Blocker
> Fix For: 0.90.0
>
>
> When splitting the WAL and encountering EOF, it's not clear what to do.
> Initial discussion of this started in http://review.hbase.org/r/74/ -
> summarizing here for brevity:
> We can get an EOFException while splitting the WAL in the following cases:
> - The writer died after creating the file but before even writing the header
> (or crashed halfway through writing the header)
> - The writer died in the middle of flushing some data - sync() guarantees
> that we can see _at least_ the last edit, but we may see half of an edit that
> was being written out when the RS crashed (especially for large rows)
> - The data was actually corrupted somehow (eg a length field got changed to
> be too long and thus points past EOF)
> Ideally we would know when we see EOF whether it was really the last record,
> and in that case, simply drop that record (it wasn't synced, so therefore we
> dont need to split it). Some open questions:
> - Currently we ignore empty files. Is it ok to ignore an empty log file if
> it's not the last one?
> - Similarly, do we ignore an EOF mid-record if it's not the last log file?
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