Is it possible to evaluate query performance without executing it?

Yes, in most DBMS and database tools, it is possible to get an estimate of query performance without actually executing it. This is achieved through analyzing the execution plan or explain plan.

For example, in PostgreSQL, the EXPLAIN command shows how the DBMS plans to execute the query, which indexes will be used, how many rows are expected to be processed, etc. This helps understand the potential complexity and cost of the query.

In Java, profiling tools or ORM tools can be used, which provide methods to obtain the query plan or estimate its costs without executing.

Thus, analyzing the execution plan is a standard way to estimate query performance in advance.