Create dbo.fn_ag_is_primary.sql

QueryTemplates/dbo.fn_ag_is_primary.sql

@@ -0,0 +1,46 @@
+USE master;
+GO
+
+CREATE OR ALTER FUNCTION dbo.fn_ag_is_primary(@AGName sysname NULL)
+RETURNS bit
+AS
+BEGIN
+	DECLARE @ServerName NVARCHAR(256)  = @@SERVERNAME 
+	DECLARE @RoleDesc NVARCHAR(60)
+
+	IF @AGName IS NULL
+	BEGIN
+		IF (SELECT COUNT(*) FROM sys.availability_groups) > 1
+		BEGIN
+			RETURN 0;
+		END
+
+		SELECT @AGName = AG.name FROM sys.availability_replicas AR 
+			INNER JOIN sys.availability_groups AG
+				ON AR.group_id = AG.group_id
+		WHERE replica_server_name = @ServerName
+	END
+	ELSE
+	BEGIN
+		IF NOT EXISTS(SELECT 1 FROM sys.availability_groups WHERE name = @AGName)
+		BEGIN
+			RETURN 0;
+		END
+	END
+
+	SELECT @RoleDesc = a.role_desc
+		FROM sys.dm_hadr_availability_replica_states AS a
+		JOIN sys.availability_replicas AS b
+			ON b.replica_id = a.replica_id
+		INNER JOIN sys.availability_groups AG
+			ON a.group_id = AG.group_id
+	WHERE b.replica_server_name = @ServerName 
+		AND  AG.name = @AGName
+
+	IF @RoleDesc = 'PRIMARY'
+	BEGIN
+		RETURN 1;
+	END
+
+	RETURN 0;
+END