This is for SQL Server 2012.
I am troubleshooting overall slow performance on a Dynamics AX environment. Everything is just slow - app itself, reports, ad-hoc, etc. Right off the bat, I can see that none of the best practices for SQL Server have been configured - MAXDOP, tempdb, trace flags specific for Dynamics, and index/fragmentation maintenance. I am pretty sure there are inefficient queries, missing or non-optimal indexes, etc.
I spent a little bit of time looking at wait stats, but now I'm wondering if I should first apply all the recommended best practices (industry-standard best practices for DynamicsAX), then troubleshoot what is slow, or dig into each issue one by one, and address it as it comes? I know some will say, don't start flipping switches until you know for sure it needs to be flipped.
How would you approach this kind of scenario?