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The system_* tables store system utilization metrics. There are three system tables, all having the same columns:
- system_now is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data. Current system utilization data is stored in system_now during the period between data collection from the Command Center agents and automatic commitment to the system_history table.
- system_tail is an external table whose data files are stored in $MASTER_DATA_DIRECTORY/gpperfmon/data. This is a transitional table for system utilization data that has been cleared from system_now but has not yet been committed to system_history. It typically only contains a few minutes worth of data.
- system_history is a regular table that stores historical system utilization metrics. It is pre-partitioned into monthly partitions. Partitions are automatically added in two month increments as needed. Administrators must drop old partitions for the months that are no longer needed.
|ctime||timestamp||Time this row was created.|
|hostname||varchar(64)||Segment or master hostname associated with these system metrics.|
|mem_total||bigint||Total system memory in bytes for this host.|
|mem_used||bigint||Used system memory in bytes for this host.|
|mem_actual_used||bigint||Used actual memory in bytes for this host (not including the memory reserved for cache and buffers).|
|mem_actual_free||bigint||Free actual memory in bytes for this host (not including the memory reserved for cache and buffers).|
|swap_total||bigint||Total swap space in bytes for this host.|
|swap_used||bigint||Used swap space in bytes for this host.|
|swap_page_in||bigint||Number of swap pages in.|
|swap_page_out||bigint||Number of swap pages out.|
|cpu_user||float||CPU usage by the Greenplum system user.|
|cpu_sys||float||CPU usage for this host.|
|cpu_idle||float||Idle CPU capacity at metric collection time.|
|load0||float||CPU load average for the prior one-minute period.|
|load1||float||CPU load average for the prior five-minute period.|
|load2||float||CPU load average for the prior fifteen-minute period.|
|quantum||int||Interval between metric collection for this metric entry.|
|disk_ro_rate||bigint||Disk read operations per second.|
|disk_wo_rate||bigint||Disk write operations per second.|
|disk_rb_rate||bigint||Bytes per second for disk write operations.|
|net_rp_rate||bigint||Packets per second on the system network for read operations.|
|net_wp_rate||bigint||Packets per second on the system network for write operations.|
|net_rb_rate||bigint||Bytes per second on the system network for read operations.|
|net_wb_rate||bigint||Bytes per second on the system network for write operations.|