Yesterday, I was solving a performance issue of a client, and I found that their in-house DBAs scheduled to restart a SQL Server at every Sunday.

I simply stopped my all tuning work and immediately set a meeting with DBA team.
To restart a SQL Server, again and again, is a very bad practice and it leads to the biggest performance issue.

You must be aware of the following points, before restarting a SQL Server.

A Plan Cache of SQL Server stores the precompiled execution plan for frequently executed of queries.
It improves the query performance by reducing a cost of creating and compiling execution plan again and again.

Apparently, most of our queries are frequently executing.

Once you restart the SQL Server, it clears the Plan Cache area, and all your queries require to create a new query plan which degrades the performance.

A Buffer Pool of SQL Server, very capable of storing the result of your frequently executed queries.

It reduces the disk/io and improves the query performance by sending a result directly from the memory area.
If a result is not available in the buffer pool, it fetches from the disk.

When you restart the SQL Server, it clears the Buffer Pool area, and it takes more time to fill it again.

The Dynamic Management Views and Functions of SQL Server, return server state information that can be used to monitor the health of a server instance, diagnose problems, and tune performance.

The DMVs and DMFs are the first tool for SQL DBA to monitor the health of SQL Server. The DMVs and DMFs store its data into the process space of sqlservr.exe.

Once you restart your SQL Server, it clears all DMVs and DMFs statistics by destroying the process of sqlservr.exe.

The rollback of uncommitted transactions of SQL Server, this is a part of SQL Server crash recovery which rollback all uncommitted transactions.

Now imagine that you are going to restart your SQL Server and few of queries are still running.

In this situation, SQL Server rollbacks all uncommitted transactions which degrade the performance and restart process might take more time to complete the action.

Get ready for SQL Server 2017 vNext for Windows, Linux, and Docker containers.
On 19th April 2017, Microsoft released a most awaited CTP 2.0 Community Technical Preview version of SQL Server 2017.

SQL Server 2017 on Windows and Linux is the best database for your Mission Critical application and data warehouse workloads.

Please visit below link to download a new CTP 2.0 of SQL Server 2017:

Link #1: Link #2: 

Following are new improvements and fixes of CTP 2.0: (Reference is taken from here)

• Added Log Shipping functionality for SQL Server Agent.
• Localized messages of mssql-conf.
• Linux path formatting are now compatible throughout the SQL Server Engine. But support for “C:\\” prefixed paths will continue.
• Enabled DMV sys.dm_os_file_exists.
• Enabled DMV sys.fn_trace_gettable.
• Added CLR Strict Security mode.
• SQL Graph.
• Resumable Online Index Rebuilds.
• Adaptive Query Processing.
• Added UTF-8 encoding for system files, including log files.
• Fixed In-memory databases location limitation.
• Add new cluster type CLUSTER_TYPE = EXTERNAL for configuring an availability group for high availability.
• Fix Availability Group Listener for read-only routing.
• Production support for Early Adoption Program (EAP) customers