Do synonyms affect remote query performance I've got a task where I need to migrate an existing database to a new server.

The database in question has stored procedures that query another database on the same server, this second database is not going to be moved.

I would love to use a synonym to point to the other database on the linked server as this will make it really easy to set up and maintain, however I want to know if the synonym is likely to cause performance problems with the execution plan, or if it's only the cross server querying that is the problem.
A synonym is just a pointer and gets simplified away prior to optimization. If you have this:

CREATE SYNONYM dbo.foo FOR OtherServer.db.dbo.blat;


Then these two will optimize the same, producing identical execution plans (both having a Remote Query operator that points at blat):

SELECT bar FROM dbo.foo;

SELECT bar FROM OtherServer.db.dbo.blat;


You can test this quite easily.