Clear magic is built on compile time. Therefore, the impact on loading time is very limited. Clear can be used for example into web function (lambda function, google cloud function) application without any problem.
The only overhead is the connection to the database; Clear allocate by default 5 connections to PostgreSQL. In the case of mono-fiber web-function projects, you may want to reduce the connection pool to 1 only:
Clear::SQL.init("postgres://[email protected]/example_db", connection_pool_size: 1)
Another good performance improvement would be to connect through PGBouncer instead of directly to the database.
Here is a simple benchmark comparing the different layers of Clear and how they impact the performance, over a 100k row very simple table:
With Model: With attributes and cursor 7.4 (135.09ms) (± 6.44%) 116409530 B/op 5.64× slowerWith Model: With cursor 8.61 (116.08ms) (± 2.82%) 97209247 B/op 4.84× slowerWith Model: With attributes 13.78 ( 72.59ms) (± 3.61%) 83101520 B/op 3.03× slowerWith Model: Simple load 100k 16.41 ( 60.94ms) (± 3.22%) 63901872 B/op 2.54× slowerHash from SQL only 30.21 ( 33.1ms) (± 5.18%) 22354496 B/op 1.38× slowerUsing: Model::Collection#pluck 41.74 ( 23.96ms) (± 8.35%) 25337128 B/op fastest
While being a bit outdated, a benchmark of the competition has been done here.
Clear stands in the middle of the crowd, being slightly slower than some other ORM over
More noticeably, Clear performs 5 to 8x faster than Ruby's ActiveRecord !