Free Microsoft DP-300 Exam Dumps

SalesSQLDb1 experiences performance issues that are likely due to out-of-date statistics and frequent blocking queries.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.

https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-tran-locks-transact-sql

https://technet.microsoft.com/windows-server-docs/failover-clustering/deploy-cloud-witness

https://azure.microsoft.com/en-us/support/legal/sla/load-balancer/v1_0/

Scenario: Authenticate database users by using Active Directory credentials.

(Create a new Azure SQL database named ResearchDB1 on a logical server named ResearchSrv01.)

Authenticate the user in SQL Database or SQL Data Warehouse based on an Azure Active Directory user:

CREATE USER [Fritz@contoso.com] FROM EXTERNAL PROVIDER;

https://docs.microsoft.com/en-us/sql/t-sql/statements/create-user-transact-sql

Scenario: SalesSQLDb1 uses database firewall rules and contained database users.

The Data Migration Assistant (DMA) helps you upgrade to a modern data platform by detecting compatibility issues that can impact database functionality in your new version of SQL Server or Azure SQL Database. DMA recommends performance and reliability improvements for your target environment and allows you to move your schema, data, and uncontained objects from your source server to your target server.

Note: SQL Managed Instance supports the following database migration options (currently these are the only supported migration methods):

Azure Database Migration Service - migration with near-zero downtime.

Native RESTORE DATABASE FROM URL - uses native backups from SQL Server and requires some downtime.

https://docs.microsoft.com/en-us/sql/dma/dma-overview

Azure Private Link enables you to access Azure PaaS Services (for example, Azure Storage and SQL Database) and Azure hosted customer-owned/partner services over a private endpoint in your virtual network.

Traffic between your virtual network and the service travels the Microsoft backbone network. Exposing your service to the public internet is no longer necessary.

https://docs.microsoft.com/en-us/azure/private-link/private-link-overview

In SQL Server, you can also minimize locking contention while protecting transactions from dirty reads of uncommitted data modifications using either:

The READ COMMITTED isolation level with the READ_COMMITTED_SNAPSHOT database option set to ON.

The SNAPSHOT isolation level.

If READ_COMMITTED_SNAPSHOT is set to ON (the default on SQL Azure Database), the Database Engine uses row versioning to present each statement with a transactionally consistent snapshot of the data as it existed at the start of the statement. Locks are not used to protect the data from updates by other transactions.

Incorrect Answers:

A: When the PARAMETERIZATION database option is set to SIMPLE, the SQL Server query optimizer may choose to parameterize the queries. This means that any literal values that are contained in a query are substituted with parameters. This process is referred to as simple parameterization. When SIMPLE parameterization is in effect, you cannot control which queries are parameterized and which queries are not.

B: You can specify that all queries in a database be parameterized by setting the PARAMETERIZATION database option to FORCED. This process is referred to as forced parameterization.

C: Delayed transaction durability is accomplished using asynchronous log writes to disk. Transaction log records are kept in a buffer and written to disk when the buffer fills or a buffer flushing event takes place. Delayed transaction durability reduces both latency and contention within the system.

Some of the cases in which you could benefit from using delayed transaction durability are:

You can tolerate some data loss.

You are experiencing a bottleneck on transaction log writes.

Your workloads have a high contention rate.

https://docs.microsoft.com/en-us/sql/t-sql/statements/set-transaction-isolation-level-transact-sql