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HBase >> mail # dev >> .oldlogs in region dir


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Re: .oldlogs in region dir
Hi,

Ah, I see Ted has that also questioned in HBASE-4010. Good.

And I was slightly wrong below, as there is a .logs and .oldlogs for the newly created regions. I agree that when there is no chance for the region to take edits before it gets the proper log, then we should drop this. Those dangling dirs do not harm, but also do not help either.

Lars

On Jul 5, 2011, at 8:39 AM, Lars George wrote:

> Hi,
>
> Could someone confirm that we dropped the replay of the .oldlogs in the region directory because it is not needed anymore? Before the master rewrite we were, just as now, creating the region and for a brief period it had its own log directory, the .oldlogs under the region directory. The HRegion.initialize() would replay it in case an edit to the region arrived in between. It would then also remove it:
>
>   public void initialize(Path initialFiles, final Progressable reporter)
>   throws IOException {
>     Path oldLogFile = new Path(regiondir, HREGION_OLDLOGFILE_NAME);
> ...
>     // Play log if one.  Delete when done.
>     doReconstructionLog(oldLogFile, minSeqIdToRecover, maxSeqId, reporter);
>     if (fs.exists(oldLogFile)) {
>       if (LOG.isDebugEnabled()) {
>         LOG.debug("Deleting old log file: " + oldLogFile);
>       }
>       fs.delete(oldLogFile, false);
>     }
> ...
>
> Now we still create that directory, but the above code has been dropped. Only the recovered.edits is replayed instead while the .oldlogs now hang around. I am not even sure when they may contain an entry, but if they don't then we can either do not use "<regiondir>/.oldlogs", but point it to the new "<regiondir>/.tmp" - or we can add a unconditional delete in the initialize as before.
>
> Create a JIRA for this?
>
> Lars