Something has to do the disk accesses. And because the physical reads on disk is often the determining factor for throughput, this must be somehow included in the optimizer. (I am aware that the optimizer does not know what is present in the cache, but it does base it's optimizing on how many pages are needed).

I am not completely aware what the

query processor

query engine

RDBMS engine

SQL-server engine

Is.

For me the database is the part which is still there if you pull the plug out of the machine.

But do not realy understand the distinction between the above mentioned processors/engines.

For me the RDBMS engine does deliver the results and does take all the neccesary actions to get those results. (Both for select and mutation statements).

The query processor ??? processes the query (compilation and execution) I assume.

The query engine ??? invokes the query processor and gets the neccesary data ???

SQL-server engine is a RDBMS engine.

But for me the borders between the different parts are a bit :crazy: vague. Sorry.

Ben