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https://issues.apache.org/jira/browse/HBASE-24255?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17094936#comment-17094936
]
Huaxiang Sun commented on HBASE-24255:
--------------------------------------
Just came cross this one. Could it be addressed in
[https://github.com/apache/hbase/pull/1584/commits/f5e00a23ddb3d60e76aa3316af8887fad4859f7e]
?
{code:java}
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/MetaTableAccessor.java
@@ -1846,6 +1846,16 @@ public class MetaTableAccessor {
qualifiers.add(qualifier);
delete.addColumns(getCatalogFamily(), qualifier,
HConstants.LATEST_TIMESTAMP);
}
+
+ // There will be race condition that a GCMultipleMergedRegionsProcedure is
scheduled while
+ // the previous GCMultipleMergedRegionsProcedure is still going on, in
this case, the second
+ // GCMultipleMergedRegionsProcedure could delete the merged region by
accident!
+ if (qualifiers.isEmpty()) {
+ LOG.info("No merged qualifiers for region " +
mergeRegion.getRegionNameAsString() +
+ " in meta table, they are cleaned up already, Skip.");
+ return;
+ }
+{code}
> GCRegionProcedure doesn't assign region from RegionServer leading to orphans
> ----------------------------------------------------------------------------
>
> Key: HBASE-24255
> URL: https://issues.apache.org/jira/browse/HBASE-24255
> Project: HBase
> Issue Type: Bug
> Components: proc-v2, Region Assignment, regionserver
> Affects Versions: 2.2.4
> Environment: hbase 2.2.4
> hadoop 3.1.3
> Reporter: Andrey Elenskiy
> Assignee: niuyulin
> Priority: Major
>
> We've found ourselves in a situation where parents of merged or split regions
> needed to be opened again on a regionserver due to having to recover from
> cluster meltdown (HBCK2's fixMeta kicks off GCMultipleMergedRegionsProcedure
> which requiters all regions to be merged to be open). Then, when a
> GCProcedure is kicked of to clean a parent region up by
> GCMultipleMergedRegionsProcedure, it ends up deleting it from hbase:meta, but
> doesn't unassign it from RegionServer leading for it to show up in "Orphan
> Regions on RegionServer" in hbck tab of HBase Master. Also, the hbase client
> doesn't detect that the region is closed either because it's still
> technically open on a regionserver (it doesn't reread hbase:meta all the
> time). The only way to recover from this is to restart regionserver which
> isn't idea as it can lead to other issues in clusters with region
> inconsistencies.
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