Percona Server

Not all dashboards in Metrics Monitor are available by default for all MySQL variants and configurations: Oracle’s MySQL, Percona Server. or MariaDB. Some graphs require Percona Server, and specialized plugins, or additional configuration.

log_slow_rate_limit

The log_slow_rate_limit variable defines the fraction of queries captured by the slow query log. A good rule of thumb is to have approximately 100 queries logged per second. For example, if your Percona Server instance processes 10_000 queries per second, you should set log_slow_rate_limit to 100 and capture every 100^th query for the slow query log.

log_slow_verbosity

log_slow_verbosity variable specifies how much information to include in the slow query log. It is a good idea to set log_slow_verbosity to full so that maximum amount of information about each captured query is stored.

slow_query_log_use_global_control

By default, slow query log settings apply only to new sessions. If you want to configure the slow query log during runtime and apply these settings to existing connections, set the slow_query_log_use_global_control variable to all.

Query Response Time Plugin

Query response time distribution is a feature available in Percona Server. It provides information about changes in query response time for different groups of queries, often allowing to spot performance problems before they lead to serious issues.

To enable collection of query response time:

1. Install the QUERY_RESPONSE_TIME plugins:

   INSTALL PLUGIN QUERY_RESPONSE_TIME_AUDIT SONAME 'query_response_time.so';
   INSTALL PLUGIN QUERY_RESPONSE_TIME SONAME 'query_response_time.so';
   INSTALL PLUGIN QUERY_RESPONSE_TIME_READ SONAME 'query_response_time.so';
   INSTALL PLUGIN QUERY_RESPONSE_TIME_WRITE SONAME 'query_response_time.so';
   

2. Set the global variable query_response_time_stats to ON:

   SET GLOBAL query_response_time_stats=ON;
   

MySQL User Statistics (userstat)

User statistics is a feature of Percona Server and MariaDB. It provides information about user activity, individual table and index access. In some cases, collecting user statistics can lead to high overhead, so use this feature sparingly.

To enable user statistics, set the userstat variable to 1.