Commercial DBMSes have way better customer support than open source DBMSes. Not only do they better understand the performance characteristics of their clients, but they have dedicated teams whose job it is to isolate corner cases where the DBMS is not optimized for a particular environment.
My statement -- there is not a whole lot you can do to tune your queries -- is about rewriting the queries themselves, such as join hints, etc. Changing RAID configurations, organizing the data physically on disk differently, etc. have no bearing on the quality of SQL an ORM generates. So what does? Well, 20 years ago many DBMSes required you to compile stored procedures in order for the cost-based optimizer to cache anything. Today, not only does SQL Server 2008 R2 support fine grained plan caching and allow you to adjust the size of that cache, but you can remove from the cache any plan you dislike. You can also force a poorly performing query to use a specific plan cache. This is one of the ideas behind the LINQ Re-Motion project for .NET.
I am really arguing about where to put work effort into, and really NOT disagreeing with you. We are talking past each other.
I personally believe, as I wrote in the author's blog comments, that an ORM based on an algebraic model would likely be better than the big and irregular ORM APIs we have today.
My statement -- there is not a whole lot you can do to tune your queries -- is about rewriting the queries themselves, such as join hints, etc. Changing RAID configurations, organizing the data physically on disk differently, etc. have no bearing on the quality of SQL an ORM generates. So what does? Well, 20 years ago many DBMSes required you to compile stored procedures in order for the cost-based optimizer to cache anything. Today, not only does SQL Server 2008 R2 support fine grained plan caching and allow you to adjust the size of that cache, but you can remove from the cache any plan you dislike. You can also force a poorly performing query to use a specific plan cache. This is one of the ideas behind the LINQ Re-Motion project for .NET.
I am really arguing about where to put work effort into, and really NOT disagreeing with you. We are talking past each other.
I personally believe, as I wrote in the author's blog comments, that an ORM based on an algebraic model would likely be better than the big and irregular ORM APIs we have today.