What is Optimizer / Query optimizer?

A key subsystem in relational database to determine the efficient way to execute a given query in a timely fashion. It transforms an input SQL query into an executable query plan. Most mainstream databases use the cost-based optimizer (CBO) which determines the best query by calculating the cost of many factors such I/O speed, number of rows to be accessed etc. Because the cost is an estimate, and also the plan needs to be generated in a timely fashion, thus the optimizer can not permutate all possible plans and pick the optimal plan.

Safer and faster database change and version control for DBAs and Developers

Bytebase is an open source, web-based database schema change and version control tool for teams. It offers a web-based collaboration workspace to help DBAs and Developers manage the lifecycle of application database schemas.