data-konzept

'Based on the number of times I see this question on forums, it must be occurring all the time. You have two different servers that, as far as you know, are identical in terms of their options and setup (although not necessarily in terms of power, think a test or pre-production system versus production). On these servers you have a database on each that, as far as you know, is the same as the other in terms of options, objects, maybe even data (although, this does mean that you have unmasked production information in your QA environment, which potentially means you’re going to jail, might want to address this, especially now that I’ve told you about it, mens rea, you’re welcome). On each database you run, as far as you know, the exact same query (whether a straight up ad hoc query, stored procedure, parameterized query, whatever). On your production server, let’s call it PROD, the query runs for 3 hours before it returns, but on the test server, let’s call it TEST, it returns in about 3 seconds.

What. The. Hell.'...

http://www.sqlservercentral.com/blogs/scarydba/2016/07/11/same-query-different-servers-different-performance-now-what/