This was an article we were meaning to write and got reminded by Szymon Guz latest PostgreSQL search_path behavior.
The PostgreSQL search_path variable allows you to control what order schemas are searched and which schemas do not require schema qualification to use tables/views/functions in the schema. The pg_catalog schema is one that never requires schema qualification even if you don't add it to your schema search_path. Schemas are searched in the order they are listed
and when creating new objects (e.g. tables, views, function, types) that are not schema qualified, they are always created in the first schema of the search path. Any objects not in a schema listed in the search_path must be schema qualified.
We've been fighting to get clients we have thinking of upgrading or creating new apps to also choose PostgreSQL in the process.
Here I'll just itemize some of the obstacles we've run into in making the sale. All of these fall under the It is not Database X line item.
By database X I mean SQL Server, MySQL, and Oracle and for us in exactly that order. Our obstacle focus is probably a bit different from others since
we are consultants to mostly Windows shops or consultants to ISVs who have to sell their applications to U.S. government agencies or units of agencies.