Added new wait types for Hyperscale

Added 4 new wait types introduced for Hyperscale database.

Author: shkale-msft

docs/relational-databases/system-dynamic-management-views/sys-dm-os-wait-stats-transact-sql.md

@@ -1,7 +1,7 @@
 ---
 title: "sys.dm_os_wait_stats (Transact-SQL) | Microsoft Docs"
 ms.custom: ""
-ms.date: "12/04/2018"
+ms.date: "05/16/2019"
 ms.prod: sql
 ms.prod_service: "database-engine, sql-database, sql-data-warehouse, pdw"
 ms.reviewer: ""
@@ -773,6 +773,10 @@ This command resets all counters to 0.
 |QUERY_TASK_ENQUEUE_MUTEX |TBD <br /> **Applies to**: [!INCLUDE[ssSQL12](../../includes/sssql11-md.md)] through [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)].| 
 |QUERY_TRACEOUT |Identified for informational purposes only. Not supported. Future compatibility is not guaranteed.| 
 |RBIO_WAIT_VLF |TBD <br /> **Applies to**: [!INCLUDE[ssSQLv14_md](../../includes/sssqlv14-md.md)] through [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)].| 
+|RBIO_RG_STORAGE |Occurs when a Hyperscale database compute node is being throttled due to delayed log consumption at the page server(s). <br /> **Applies to**: Azure SQL Database Hyperscale.|
+|RBIO_RG_DESTAGE |Occurs when a Hyperscale database compute node is being throttled due to delayed log consumption by the long term log storage. <br /> **Applies to**: Azure SQL Database Hyperscale.|
+|RBIO_RG_REPLICA |Occurs when a Hyperscale database compute node is being throttled due to delayed log consumption by the readable secondary replica node(s). <br /> **Applies to**: Azure SQL Database Hyperscale.|
+|RBIO_RG_LOCALDESTAGE |Occurs when a Hyperscale database compute node is being throttled due to delayed log consumption by the log service. <br /> **Applies to**: Azure SQL Database Hyperscale.|
 |RECOVER_CHANGEDB |Occurs during synchronization of database status in warm standby database.| 
 |RECOVERY_MGR_LOCK |TBD <br /> **Applies to**: [!INCLUDE[ssSQL15_md](../../includes/sssql15-md.md)] through [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)].| 
 |REDO_THREAD_PENDING_WORK |TBD <br /> **Applies to**: [!INCLUDE[ssSQL12](../../includes/sssql11-md.md)] through [!INCLUDE[ssCurrent](../../includes/sscurrent-md.md)].|