Viraj Jasani created HBASE-26459: ------------------------------------ Summary: HMaster should move non-meta region only if meta is ONLINE Key: HBASE-26459 URL: https://issues.apache.org/jira/browse/HBASE-26459 Project: HBase Issue Type: Improvement Affects Versions: 1.7.1 Reporter: Viraj Jasani Fix For: 1.7.2
Any non-meta region movement has dependency over meta's availability, hence it is important for any non-meta region to wait for meta to be assigned and be available for scan before attempting to move non-meta region. This concept has already been well managed by SCP (ServerCrashProcedure) on HBase 1.x and 2.x versions. However, for 1.x versions, HMaster#move API doesn't check for any prerequisite of meta being available before attempting to move any non-meta region. On the other hand, 2.x versions already have TransitRegionStateProcedure (TRSP) in place that uses lock _LockState.LOCK_EVENT_WAIT_ in case if meta is not yet assigned and loaded in AssignmentManager's memory: {code:java} @Override protected boolean waitInitialized(MasterProcedureEnv env) { if (TableName.isMetaTableName(getTableName())) { return false; } // First we need meta to be loaded, and second, if meta is not online then we will likely to // fail when updating meta so we wait until it is assigned. AssignmentManager am = env.getAssignmentManager(); return am.waitMetaLoaded(this) || am.waitMetaAssigned(this, getRegion()); } {code} For 1.x versions, it is recommended to introduce configurable wait time in master's region move API for non-meta region movement until meta region is available. If meta remains in transition after the wait time elapses, we should fail fast and avoid non-meta region move. -- This message was sent by Atlassian Jira (v8.20.1#820001)