User Resource Monitoring¶
In the multi-tenant management framework, you can query the real-time usage of all user resources (including the memory, number of CPU cores, storage space, temporary space, operator spilling space, and I/Os) in real time through the system views PG_TOTAL_USER_RESOURCE_INFO and PGXC_TOTAL_USER_RESOURCE_INFO and the function GS_WLM_USER_RESOURCE_INFO. You can also query the system catalog GS_WLM_USER_RESOURCE_HISTORY and system view PGXC_WLM_USER_RESOURCE_HISTORY for the historical usage of user resources.
Precautions¶
The CPU, I/O, and memory usage of all jobs on fast and slow lanes (simple jobs on fast lanes and complex jobs on slow lanes) can be monitored.
Currently, fast lane jobs have no memory or CPU limits. They may use too many resources and go over the resource limit.
In the DN monitoring view, I/O, memory, and CPU display the resource usage and limits of resource pools.
In the CN monitoring view, I/O, memory, and CPU display the total resource usage and limit of all DN resource pools in the cluster.
The DN monitoring information is updated every 5 seconds. CNs collect monitoring information from DNs every 5 seconds. Because each instance updates or collects user monitoring information independently, the monitoring information update time on each instance may be different.
The auxiliary thread automatically invokes the persistence function every 30 seconds to make user monitoring data persistent. So, normally, you don't have to do this.
When there are a large number of users and a large cluster, querying such real-time views will cause network latency due to the real-time communication overhead between CNs and DNs.
Resources are not monitored for an initial administrator.
Procedure¶
Query all users' resource quotas and real-time resource usage.
SELECT * FROM PG_TOTAL_USER_RESOURCE_INFO;
The result view is as follows:
username | used_memory | total_memory | used_cpu | total_cpu | used_space | total_space | used_temp_space | total_temp_space | used_spill_space | total_spill_space | read_kbytes | write_kbytes | read_counts | write_counts | read_speed | write_speed | send_speed | recv_speed -----------------------+-------------+--------------+----------+-----------+------------+-------------+-----------------+------------------+------------------+-------------------+-------------+--------------+-------------+--------------+------------+-------------+------------+------------ perfadm | 0 | 0 | 0 | 0 | 0 | -1 | 0 | -1 | 0 | -1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 usern | 0 | 17250 | 0 | 48 | 0 | -1 | 0 | -1 | 0 | -1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 (2 rows)
The I/O resource monitoring fields (read_kbytes, write_kbytes, read_counts, write_counts, read_speed, and write_speed) can be available only when the GUC parameter described in enable_user_metric_persistent is enabled.
For details about each column, see PG_TOTAL_USER_RESOURCE_INFO.
Query a user's resource quota and real-time resource usage.
SELECT * FROM GS_WLM_USER_RESOURCE_INFO('username');
The query result is as follows:
userid | used_memory | total_memory | used_cpu | total_cpu | used_space | total_space | used_temp_space | total_temp_space | used_spill_space | total_spill_space | read_kbytes | write_kbytes | read_counts | write_counts | read_speed | write_speed | send_speed | recv_speed --------+-------------+--------------+----------+-----------+------------+-------------+-----------------+------------------+------------------+-------------------+-------------+--------------+-------------+--------------+------------+-------------+------------+------------ 16407 | 18 | 1655 | 6 | 19 | 13787176 | -1 | 0 | -1 | 0 | -1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 (1 row)
Query all users' resource quotas and historical resource usage.
SELECT * FROM GS_WLM_USER_RESOURCE_HISTORY;
The query result is as follows:
username | timestamp | used_memory | total_memory | used_cpu | total_cpu | used_space | total_space | used_temp_space | total_temp_space | used_spill_space | total_spill_space | read_kbytes | write_kbytes | read_counts | write_counts | read_speed | write_speed | send_speed | recv_speed -----------------------+-------------------------------+-------------+--------------+----------+-----------+------------+-------------+-----------------+------------------+------------------+-------------------+-------------+--------------+-------------+--------------+-------------+-------------+------------+------------ usern | 2020-01-08 22:56:06.456855+08 | 0 | 17250 | 0 | 48 | 0 | -1 | 0 | -1 | 88349078 | -1 | 45680 | 34 | 5710 | 8 | 320 | 0 | 0 | 0 userg | 2020-01-08 22:56:06.458659+08 | 0 | 15525 | 33.48 | 48 | 0 | -1 | 0 | -1 | 110169581 | -1 | 17648 | 23 | 2206 | 5 | 123 | 0 | 0 | 0 userg1 | 2020-01-08 22:56:06.460252+08 | 0 | 13972 | 33.48 | 48 | 0 | -1 | 0 | -1 | 136106277 | -1 | 17648 | 23 | 2206 | 5 | 123 | 0 | 0 | 0
For the system catalog in GS_WLM_USER_RESOURCE_HISTORY, data in the PG_TOTAL_USER_RESOURCE_INFO view is periodically saved to historical tables only when the GUC parameter enable_user_metric_persistent is enabled.
For details about each column, see GS_WLM_USER_RESOURCE_HISTORY.