[jira] [Commented] (HBASE-16455) Provide API for obtaining highest file number among all the WAL files

["Ted Yu (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-16455?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15427938#comment-15427938 ] 

Ted Yu commented on HBASE-16455:
--------------------------------

The following log was obtained when I worked on HBASE-14450:
{code}
2016-08-18 19:12:33,355 INFO  [rs(192.168.0.14,52286,1471572715945)-backup-pool19-thread-1] regionserver.LogRollBackupSubprocedure$RSRollLogTask(80): Trying to roll log in backup              subprocedure, current log number: 1471572720163 highest: 1471572748368 on 192.168.0.14,52286,1471572715945
{code}
1471572720163 was the filenum for the WAL returned by getWAL(null). 1471572748368 was the highest filenum obtained by iterating all outstanding WAL files.

> Provide API for obtaining highest file number among all the WAL files
> ---------------------------------------------------------------------
>
>                 Key: HBASE-16455
>                 URL: https://issues.apache.org/jira/browse/HBASE-16455
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Ted Yu
>            Assignee: Ted Yu
>         Attachments: 16455.v1.txt
>
>
> Currently RegionServerServices has the following API:
> {code}
>   WAL getWAL(HRegionInfo regionInfo) throws IOException;
> {code}
> Caller can only obtain filenum for a specific WAL.
> When multi wal is in use, we should add API for obtaining highest file number among all the outstanding WAL files.
> User can pass null to getWAL() method above, but the filenum for the returned WAL may not be the highest among all the WAL files.
> See log snippet in the first comment.



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