DP-300 Administering Microsoft Azure SQL Solutions

SalesSQLDb1 experiences performance issues that are likely due to out-of-date statistics and

frequent blocking queries.

A: Use sys.dm_pdw_nodes_tran_locks instead of sys.dm_tran_locks from Azure Synapse Analytics

(SQL Data Warehouse) or Parallel Data Warehouse.

E: Example:

The following query will show blocking information.

SELECT

t1.resource_type,

t1.resource_database_id,

t1.resource_associated_entity

_id, t1.request_mode,

t1.request_session_id,

t2.blocking_session_id

FROM sys.dm_tran_locks as t1

INNER JOIN sys.dm_os_waiting_tasks as t2

ON t1.lock_owner_address = t2.resource_address;

Note: Depending on the system you’re working with you can access these wait statistics from one of
three locations: sys.dm_os_wait_stats: for SQL Server
sys.dm_db_wait_stats: for Azure SQL Database
sys.dm_pdw_nodes_os_wait_stats: for Azure SQL Data Warehouse
Incorrect Answers:
F: sys.dm_tran_locks returns information about currently active lock manager resources in SQL
Server 2019 (15.x). Each row represents a currently active request to the lock manager for a lock that
has been granted or is waiting to be granted.
Instead use sys.dm_pdw_nodes_tran_locks.