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https://issues.apache.org/jira/browse/HBASE-22567?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16878102#comment-16878102
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Wellington Chevreuil commented on HBASE-22567:
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Thanks for looking into this, [~stack]! I had pushed a new commit addressing
some of your suggestions in the PR, still working on the remaining ones. For
the ones I had replied and looks ok on latest commit, could you mark as
resolved in the PR? As for your previous comments, some thoughts below:
{quote}The hard part w/ this command will be when to use it.{quote}
Indeed, maybe we need to document it with some symptoms examples. On the cases
this had been useful, one clear sign was that even namespace table had no
region in meta, and master startup would never complete.
{quote}Could this command rebuild meta if table totally missing in meta but
present in hdfs?{quote}
Right now, it only takes care of region information, but I guess we could
extend it to also cover missing table info in meta.
> HBCK2 addMissingRegionsToMeta
> -----------------------------
>
> Key: HBASE-22567
> URL: https://issues.apache.org/jira/browse/HBASE-22567
> Project: HBase
> Issue Type: New Feature
> Reporter: Wellington Chevreuil
> Assignee: Wellington Chevreuil
> Priority: Major
>
> Following latest discussion on HBASE-21745, this proposes an hbck2 command
> that allows for inserting back regions missing in META that still have
> *regioninfo* available in HDFS. Although this is still an interactive and
> simpler version than the old _OfflineMetaRepair_, it still relies on hdfs
> state as the source of truth, and performs META updates mostly independently
> from Master (apart from requiring Meta table been online).
> For a more detailed explanation on this command behaviour, pasting _command
> usage_ text:
> {noformat}
> To be used for scenarios where some regions may be missing in META,
> but there's still a valid 'regioninfo' metadata file on HDFS.
> This is a lighter version of 'OfflineMetaRepair' tool commonly used for
> similar issues on 1.x release line.
> This command needs META to be online. For each table name passed as
> parameter, it performs a diff between regions available in META,
> against existing regions dirs on HDFS. Then, for region dirs with
> no matches in META, it reads regioninfo metadata file and
> re-creates given region in META. Regions are re-created in 'CLOSED'
> state at META table only, but not in Masters' cache, and are not
> assigned either. A rolling Masters restart, followed by a
> hbck2 'assigns' command with all re-inserted regions is required.
> This hbck2 'assigns' command is printed for user convenience.
> WARNING: To avoid potential region overlapping problems due to ongoing
> splits, this command disables given tables while re-inserting regions.
> An example adding missing regions for tables 'table_1' and 'table_2':
> $ HBCK2 addMissingRegionsInMeta table_1 table_2
> Returns hbck2 'assigns' command with all re-inserted regions.{noformat}
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