7.5.11.2 Memory Monitoring

If health_monitor.memory_running=ON, Health Monitor samples system memory and the MySQL server process at the interval specified by health_monitor.memory_sample_rate. Measurements are stored in the Performance Schema tables health_system_memory and health_process_memory. The default memory sampling interval is 60 seconds and the default retention is 86400 seconds, providing capacity for 1440 measurements in each table.

The system memory table distinguishes free memory from available memory. Available memory is the platform-defined estimate used for warning thresholds. On Linux it estimates memory available for new applications without swapping. Memory consumption by other processes on the host can therefore cause Health Monitor memory warnings. Platform-specific metrics can be NULL when unavailable.

The default memory sampling interval is 60 seconds and the default retention is 86400 seconds, providing capacity for 1440 measurements in each table.

health_monitor.memory_usage_warning_level_1, health_monitor.memory_usage_warning_level_2 and health_monitor.memory_usage_warning_level_3 define absolute available-memory warning thresholds, with defaults of 1024, 500, and 100 MiB, respectively. Health Monitor reports the most severe applicable warning and reports changes as memory decreases or recovers. These are available-memory thresholds rather than percentages of process memory in use.

Memory warnings do not automatically shut down the server or terminate queries in response to low memory.