We have a database with 1000 tables, 1400 stored procedures and mor that 3000 triggers. I have extracted the database metadata and executed it ( with IBExpert) against Firebird 2.1 and Firebird 2.5. In firebird 2.1 the script takes 6 minutes in execute but in FB 2.5 more than 5 hours. The difference between both is the time FB 2.5 takes to compile the stored procedures, while version 2.1 takes milliseconds, 2.5 takes more than 10 seconds.
Once tha database is created, i have connected to both and recompile some stored procedures, but with the same results. While 2.1 takes milliseconds, 2.5 takes more than 10 seconds.
I can attach the database script.