#3504 sp_BlitzFirst Azure SQL DB

More accurate startup time detection. Closes #3504.

Author: BrentOzar

sp_BlitzFirst.sql

@@ -281,16 +281,23 @@ BEGIN
 
     /* Set start/finish times AFTER sp_BlitzWho runs. For more info: https://github.com/BrentOzarULTD/SQL-Server-First-Responder-Kit/issues/2244 */
     IF @Seconds = 0 AND SERVERPROPERTY('EngineEdition') = 5 /*SERVERPROPERTY('Edition') = 'SQL Azure'*/
-        WITH WaitTimes AS (
-            SELECT wait_type, wait_time_ms,
-                NTILE(3) OVER(ORDER BY wait_time_ms) AS grouper
-                FROM sys.dm_os_wait_stats w
-                WHERE wait_type IN ('DIRTY_PAGE_POLL','HADR_FILESTREAM_IOMGR_IOCOMPLETION','LAZYWRITER_SLEEP',
-                                    'LOGMGR_QUEUE','REQUEST_FOR_DEADLOCK_SEARCH','XE_TIMER_EVENT')
-        )
-        SELECT @StartSampleTime = DATEADD(mi, AVG(-wait_time_ms / 1000 / 60), SYSDATETIMEOFFSET()), @FinishSampleTime = SYSDATETIMEOFFSET()
-            FROM WaitTimes
-            WHERE grouper = 2;
+		BEGIN
+		/* Use the most accurate (but undocumented) DMV if it's available: */
+		IF EXISTS(SELECT * FROM sys.all_columns ac WHERE ac.object_id = OBJECT_ID('sys.dm_cloud_database_epoch') AND ac.name = 'last_role_transition_time')
+			SELECT @StartSampleTime = DATEADD(MINUTE,DATEDIFF(MINUTE, GETDATE(), GETUTCDATE()),last_role_transition_time) , @FinishSampleTime = SYSDATETIMEOFFSET()
+				FROM sys.dm_cloud_database_epoch;
+		ELSE
+			WITH WaitTimes AS (
+				SELECT wait_type, wait_time_ms,
+					NTILE(3) OVER(ORDER BY wait_time_ms) AS grouper
+					FROM sys.dm_os_wait_stats w
+					WHERE wait_type IN ('DIRTY_PAGE_POLL','HADR_FILESTREAM_IOMGR_IOCOMPLETION','LAZYWRITER_SLEEP',
+										'LOGMGR_QUEUE','REQUEST_FOR_DEADLOCK_SEARCH','XE_TIMER_EVENT')
+			)
+			SELECT @StartSampleTime = DATEADD(mi, AVG(-wait_time_ms / 1000 / 60), SYSDATETIMEOFFSET()), @FinishSampleTime = SYSDATETIMEOFFSET()
+				FROM WaitTimes
+				WHERE grouper = 2;
+		END
     ELSE IF @Seconds = 0 AND SERVERPROPERTY('EngineEdition') <> 5 /*SERVERPROPERTY('Edition') <> 'SQL Azure'*/
         SELECT @StartSampleTime = DATEADD(MINUTE,DATEDIFF(MINUTE, GETDATE(), GETUTCDATE()),create_date) , @FinishSampleTime = SYSDATETIMEOFFSET()
             FROM sys.databases