The Slow Query Log. This is due to the additional routines needed to analyze each query as well as the IO needed to write the necessary queries to the log file. Slow Query Log Overview.
For example a query executed hundreds of times per second may be more important to optimize than a query only executed once daily even if the latter takes many times longer. We have a MySQL 5152 Percona Server 116 instance that suddenly started logging every single query to the slow query log. This allows you to find inefficient SQL queries that can be optimized to improve database performance.
Slow query logs are disabled by default and can be enabled to assist with identifying performance bottlenecks during troubleshooting.
Where long_query_time - time taken by an SQL query to be executed in seconds. This is due to the additional routines needed to analyze each query as well as the IO needed to write the necessary queries to the log file. For example a query executed hundreds of times per second may be more important to optimize than a query only executed once daily even if the latter takes many times longer. Set global log_slow_queries 1.