Why is running a query on SQL Azure so much slower?

Question

I created a trial account on Azure, and I deployed my database from SmarterAsp.

When I run a pivot query on SmarterAsp\\MyDatabase, the re

Answer 1

(Update: the original question has been changed to also ask how to optimise the query - which is a good question as well. The original question was why the difference which is what this answer is about).

The performance of individual queries is heavily affected by the performance tiers. I know the documentation implies the tiers are about load, that is not strictly true.

I would re-run your test with an S2 database as a starting point and go from there.

Being on a trial subscription does not in itself affect performance, but with the free account you are probably using a B level which isn't really useable by anything real - certainly not for a query that takes 2 seconds to run locally.

Even moving between, say, S1 and S2 will show a noticeable difference in performance of an individual query. If you want to experiment, do remember you are charged a day for "any part of a day", which is probably okay for S level but be careful when testing P level.

For background; when Azure introduced the new tiers last year, they changed the hosting model for SQL. It used to be that many databases would run on a shared sqlserver.exe. In the new model, each database effectively gets its own sqlserver.exe that runs in a resource constrained sandbox. That is how they control the "DTU usage" but also affects general performance.