data-konzept

'This topic describes improvements made to the SQL Server Database Engine for SQL Server 2017. Click the links for more information on each item.

Enhancements

• CLR uses Code Access Security (CAS) in the .NET Framework, which is no longer supported as a security boundary. A CLR assembly created with PERMISSION_SET = SAFE may be able to access external system resources, call unmanaged code, and acquire sysadmin privileges. Beginning with SQL Server 2017, an sp_configure option called clr strict security is introduced to enhance the security of CLR assemblies. clr strict security is enabled by default, and treats SAFE and EXTERNAL_ACCESS assemblies as if they were marked UNSAFE. The clr strict security option can be disabled for backward compatibility, but this is not recommended. Microsoft recommends that all assemblies be signed by a certificate or asymmetric key with a corresponding login that has been granted UNSAFE ASSEMBLY permission in the master database. CLR assemblies can be added to a whitelist, as a work-around for the clr strict security feature. sp_add_trusted_assembly, sp_drop_trusted_assembly, and sys.trusted_asssemblies are added to support the white list of trusted assemblies. For more information, see CLR strict security. 

• A new, DMF sys.dm_db_log_stats, is introduced to expose summary level attributes and information on transaction log files; useful for monitoring the health of the transaction log. 

• Resumable online index rebuild. Resumable online index rebuild allows you to resume an online index rebuild operation from where it stopped after a failure (such as a failover to a replica or insufficient disk space). You can also pause and later resume an online index rebuild operation. For example, you might need to temporarily free up systems resources in order to execute a high priority task or complete the index rebuild in another maintenance window if the available maintenance windows is too short for a large table. Finally, resumable online index rebuild does not require significant log space, which allows you to perform log truncation while the resumable rebuild operation is running. See ALTER INDEX and Guidelines for online index operations'...

https://docs.microsoft.com/en-us/sql/database-engine/whats-new-in-sql-server-2017