SalesSQLDb1 experiences performance issues that are likely due to out-of-date statistics and frequent blocking queries.
Seeing a Count of All Active SQL Server Wait Types.
Sometimes we're trying to diagnose a problem and we want to know if we're seeing a large number of wait types occurring. We can do this using sys.dm_exec_requests because the current wait type being experienced is presented. Therefore, if we filter out any background or sleeping tasks, we can get a picture of what the waits are for active requests and we can also see if we have a problem. Here's the query:
SELECT COALESCE(wait_type, 'None') AS wait_type, COUNT(*) AS Total
FROM sys.dm_exec_requests -
WHERE NOT status IN ('Background', 'Sleeping')
GROUP BY wait_type
ORDER BY Total DESC;
Here is an example of the query output:

We see that we have two LCK_M_S wait types. This is the wait type we get when we have requests waiting on obtaining a shared lock. We can then query along with sys.dm_tran_locks to determine what types of locks these active requests were trying to obtain:
SELECT L.request_session_id, L.resource_type,L.resource_subtype, L.request_mode,
L.request_type
FROM sys.dm_tran_locks AS L
JOIN sys.dm_exec_requests AS DER
ON L.request_session_id = DER.session_id
WHERE DER.wait_type = 'LCK_M_S';
Incorrect:
Not A: Azure SQL database does not have sys.dm_pdw_nodes_tran_locks.
Not E: Azure SQL database does not have sys.dm_pdw_nodes_os_wait_stats.
Reference:
https://www.mssqltips.com/sqlservertip/5521/understanding-and-using-sql-server-sysdmexecrequests/