In Oracle, a query is a request for data from a database. Query performance is the amount of time it takes for a query to be executed and return results. Slow query performance can impact the overall performance of an application or system. Therefore, it is important to be able to check the performance of queries in order to identify and resolve any issues.
There are a number of ways to check the performance of a query in Oracle. One way is to use the EXPLAIN PLAN command. This command will show you the execution plan for a query, which can help you to identify any potential bottlenecks. Another way to check query performance is to use the DBMS_PROFILER package. This package provides a number of functions that can be used to collect performance data about queries.