Just-in-time compilation of SQL statements is one of the new features in PostgreSQL 11. Just-in-Time compilation (JIT) is the process of turning some form of interpreted program evaluation into a native program and doing so at runtime. While doing some testing and benchmarking with JIT it appears that PostgreSQL 11 is about 29.31% faster at executing the TPC-H Q1 query than PostgreSQL 10. You could get details from https://www.citusdata.com/blog/2018/09/11/postgresql-11-just-in-time/.
