You cannot enable trace flags (globally or by session) within Azure SQL Database but did you know that some global trace flags are enabled by default?
What is on?
Well, a lot of these are not documented anywhere. Some are for example trace flag 1800 which enables SQL Server optimization when disks of different sector sizes are used for primary and secondary replica log files, in SQL Server Always On AGs and Log Shipping environments. Other trace flags? Who knows! Well I would love a trip to Redmond to find out….I’ll keep dreaming.