Hello there !
I'm pleased to have the opportunity to ask my first question here, I hope I'll do good.
So, I'm more of a SQL Server developer/DBA and I'm currently working with our ERP teams to improve performance on the D365 FO solution we're making for our client. During my audit, I've found that the Legacy Cardinality Estimator was being used. With a little more research, I learn that it was actually a recommended option for Ax 2012 R3 runnng on SQL Server 2014 and above.
Since we're in SQL Database on Azure, I was wondering if that option was still relevant, hoping improvements were made since 2012 R3 version of Ax, so we can use the new cardinality Estimation, but I've found an article on MS Docs about the migration of a SQL Server instance to SQL DB on Azure: https://docs.microsoft.com/en-us/dynamics365/unified-operations/dev-itpro/database/copy-database-from-sql-server-to-azure-sql
In this article, it is stated to alter the default configuration of the Ax database to set the LEGACY_CARDINALITY_ESTIMATION to 1, meaning we won't use the brand new CE and have to stick with the old guy.
Has anyone ever did some perf testing with/without that option? Is a benchmark available somewhere? It seems to me that, at some point, using Legacy CE could do more harm than good. Even in our ERP team, the question is dividing people. We have the means to test it ourselves but I wouldn't like to alter a configuration that is recommended by MS.
Cheers,
Paul D.