Testing application’s queries (the excerpt from "Migration Guide To Firebird 3")

Changing from one Firebird version to another can cause problems with existing queries, ranging from bad performance to total failure when queries use newly reserved words or incorrect SQL that had been accepted.

An application often includes of hundreds of queries, from browsing information on the screen, to creating reports, to data entry and validation. There could be external scripts and query generators which generate SQL queries on the fly, so it is not possible to check all combinations of SQL queries even with the thorough check-up of application's sources.

HQbird FBScanner from IBSurgeon is a tool that can help you check that existing applications work with Firebird 3 and find out if there are errors or slowness in SQL queries of migrating applications. FBScanner is a part of HQbird Standard, the package of analysis tools that monitor and optimize Firebird servers. It allows you to log queries on your current version of Firebird and test them on the new Firebird server.  

FBScanner works as a proxy between the clients and the server, logging all communications: connections, transactions, SQL statements texts, number of fetches, SQL plans, errors, and prepare and execution times for the queries.

You can install FBScanner while using your current version of Firebird; configure it to monitor the communication and to store queries in a log database. The most popular configuration is to install FBScanner on the same server, on the port 3050 and change Firebird port to other values (3053, for example): in this case existing Firebird applications will continue to work with the database(s) on the server without any change in their connection  string: