Re:Bye Bye Mongo, Hello Postgres
by jacques_chester on Wednesday December 19, 2018 @06:45PM
(#18721124)
True, if
1. You start from a normalized schema.
2. You denormalize in a structured way (eg dimensional modelling), rather than any old how.
3. You test the change.
Database query planners work better when they can take logically-safe shortcuts in their work. In large part that comes down to a properly-constructed schema.
Denormalizing makes it harder for the query planner. It also means you will probably lose out on future query planner enhancements.
Generally speaking, if someone wants to denormalize, I want to know the actual business value created and that the business risk is properly understood.
1. You start from a normalized schema.
2. You denormalize in a structured way (eg dimensional modelling), rather than any old how.
3. You test the change.
Database query planners work better when they can take logically-safe shortcuts in their work. In large part that comes down to a properly-constructed schema.
Denormalizing makes it harder for the query planner. It also means you will probably lose out on future query planner enhancements.
Generally speaking, if someone wants to denormalize, I want to know the actual business value created and that the business risk is properly understood.