Sql-server – Is Synonyms to tables cost effective within SQL Server 2016

According to this post -

As a synonym is an abstraction/alternative name for an already existing database object, in the case of a table, index behaviour is identical to that of the underlying object i.e. when execution plans are generated, the same plan is generated irrespective of using the table name or corresponsing synonym.

You can verify the execution plans when using both the regular object and the synonym to see if they generate the same plan.

This post has a similar question:

How does the use of synonyms effect performance?

More specifically, are synonyms replaced with fully qualified names in execution plans? It would seem to me that any synonym has to be resolved to the actual object so any query or procedure that doesn't have a cached plan is going to have an extra step in mapping the synonym to an actual object. I'm thinking there would be a very small performance hit in this. Perhaps a slightly larger hit when the synonym references an object on a different database and slightly larger still when on a different server.

The answer given was

They are swapped out in the Bind phase of query execution same as a view would be expanded. This happens before the Optimization phase where the execution plan is generated so while you'll still see a reference to the synonym in the query text you will only see references to the objects the synonyms point to in the execution plan's operators.

Any performance hit, if you want to even call it that, that might be associated with using synonym is not at all worth being concerned about.

I'm sure Paul White (or another expert will provide a definitive response).