Install patch SQL server 2016 need restart??

For SQL Server 2016, installing a Cumulative Update (CU) or Service Pack (SP) generally requires a restart of the SQL Server instance, and a restart of the Windows server may also be required if files are in use.

From the SQL Server 2016 servicing documentation:

• Cumulative Updates may require a computer restart after applying the update.
• The SQL Server service is stopped and restarted as part of the update process; the instance cannot remain active for normal workload during patching.

Therefore:

• Plan for downtime of the SQL Server instance when applying CU/SP.
• Expect that the setup may prompt for or require a restart of the operating system if certain components are in use.

References:

• KB4135048 - Cumulative Update 1 for SQL Server 2016 SP2
• KB4488536 - Cumulative Update 6 for SQL Server 2016 SP2
• KB5000645 - Cumulative Update 16 for SQL Server 2016 SP2
• Security update deployment information: August 8, 2017