Monitoring Feature

Last updated: 2020-01-17 10:50:41

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Performance Monitoring

To make it easier for you to view and stay up to date with how instances work, TencentDB for MySQL provides a wide variety of performance monitoring metrics and convenient monitoring features (custom view, time comparison, merged monitoring metrics, etc). You can log in to the TencentDB for MySQL Console, and view them in Instance Monitoring on the instance management page.

  • If the number of tables in a single instance exceeds one million, database monitoring may be affected. Please control this value appropriately and make sure that it is below one million.

Types of Instances for Monitoring

TencentDB for MySQL master, read-only, and disaster recovery instances can be monitored, and each instance is provided with a separate monitoring view for easy query.

Types of Monitoring

Four types of monitoring are available for TencentDB for MySQL: resource monitoring, engine monitoring (general), engine monitoring (extended), and deployment monitoring. You can view the metrics of different monitoring types to gain a quick and accurate understanding of how instances perform and operate.

  • Resource monitoring provides monitoring data of CPU, memory, disk, and network.
  • Engine monitoring (general) provides monitoring data of the number of connections, locks, hotspot tables, and slow queries, helping you troubleshoot issues and optimize the performance.
  • Engine monitoring (extended) provides a wider variety of engine-related monitoring metrics so as to assist you in identifying existing or potential database problems as much as possible.
  • Deployment monitoring provides monitoring metrics with regard to master-slave delay.
  • Deploy monitoring on the master: When the monitored instance is a master instance which is not a slave of any instance, replicating relevant monitoring data from the master won't work, and the IO and SQL threads are disabled. Replicating relevant monitoring data can work and the IO and SQL threads can be enabled only when the monitored instance is a disaster recovery or a read-only instance.
  • Deploy monitoring on the slave: The master instance and disaster recovery instance in HA edition come in a one-master-one-slave architecture by default. As a result, replicating relevant monitoring data from the slave can work only when the monitored instance is a master or disaster recovery instance. Such data can be used to reflect the delay distance and time between the master or disaster recovery instance and its hidden slave nodes. You are recommended to keep an eye out for the relevant monitoring data of the slave. If the master or disaster recovery instance fails, its monitored hidden slave nodes can be promoted into the master instance quickly.

Monitoring Granularity

TencentDB for MySQL has adopted an adaptive policy for monitoring granularity since August 11, 2018, which means that you cannot select a monitoring granularity as desired for the time being. In addition, TencentDB for MySQL supports free monitoring at a granularity of 5 seconds. If fees will be charged for monitoring, we will inform you in advance. Below is the adaptive policy:

Time Span Monitoring Granularity Adaptation Description Retention Period
(0h, 4h] 5 seconds The time span is below 4 hours, and the monitoring granularity is 5 seconds 1 day
(4h, 2d] 1 minute The time span is above 4 hours but below 2 days, and the monitoring granularity is 1 minute 15 days
(2d, 10d] 5 minutes The time span is above 2 days but below 10 days, and the monitoring granularity is 5 minutes 31 days
(10d, 30d] 1 hour The time span is above 10 days but below 30 days, and the monitoring granularity is 1 hour 62 days

Currently, you can view monitoring data of TencentDB for MySQL in the past 30 days.

Monitoring Metrics

Cloud Monitor provides the following monitoring metrics for TencentDB for MySQL instances:

Metric Name Metric Unit Dimension Meaning
Queries per second qps Queries/second Instance The number of SQL statements executed by the database per second (including insert, select, update, delete, and replace). QPS mainly represents the actual processing capability of the TencentDB instance
Number of slow queries slow_queries - Instance Number of queries that take more than long_query_time second(s) to be executed
Number of full table scans select_scan Scans/second Instance Number of full table scans executed per second
Number of queries select_count Queries/second Instance Number of queries executed per second
Number of updates com_update Updates/second Instance Number of updates executed per second
Number of deletions com_delete Deletions/second Instance Number of deletions executed per second
Number of insertions com_insert Insertions/second Instance Number of insertions executed per second
Number of replacements com_replace Replacements/second Instance Number of replacements executed per second
Total number of requests queries Requests/second Instance All executed SQL statements such as set and show.
Number of active connections threads_connected - Instance Number of currently enabled connections
Query rate query_rate % Instance Actual QPS/recommended QPS
Used disk capacity real_capacity MB Instance This includes only MySQL's data directories but not logs such as binlog, relaylog, undolog, errorlog, and slowlog
Occupied disk capacity capacity MB Instance This includes MySQL's data directories and logs such as binlog, relaylog, undolog, errorlog, and slowlog
Amount of data sent bytes_sent MB/s Instance Number of bytes sent per second
Amount of data received bytes_received MB/s Instance Number of bytes received per second
Disk utilization volume_rate % Instance Used disk capacity/purchased instance capacity
Query cache hit rate qcache_hit_rate % Instance Query cache hit rate
Query cache utilization qcache_use_rate % Instance Query cache utilization
Number of waited table locks table_locks_waited Locks/second Instance Number of table locks due to the failure to obtain tables immediately
Number of temp tables created_tmp_tables Tables/second Instance Number of temp tables created per second.
InnoDB cache hit rate innodb_cache_hit_rate % Instance InnoDB engine cache hit rate
InnoDB cache utilization innodb_cache_use_rate % Instance InnoDB engine cache utilization
Number of InnoDB disk reads innodb_os_file_reads Reads/second Instance Number of reads to disk files by the InnoDB engine per second
Number of InnoDB disk writes innodb_os_file_writes Writes/second Instance Number of writes to disk files by the InnoDB engine per second
Number of InnoDB fsync calls innodb_os_fsyncs Calls/second Instance Number of calls of the fsync function by the InnoDB engine per second
Number of tables currently opened by InnoDB innodb_num_open_files - Instance Number of tables currently opened by the InnoDB engine
MyISAM cache hit rate key_cache_hit_rate % Instance MyISAM engine cache hit rate
MyISAM cache utilization key_cache_use_rate % Instance MyISAM engine cache utilization
CPU utilization cpu_use_rate % Instance Overuse is permitted while idle. The CPU utilization may exceed 100%
Memory utilization memory use rate % Instance Overuse is permitted while idle. The memory utilization may exceed 100%
Memory usage memory use MB Instance Overuse is permitted while idle. The actual memory usage may exceed the purchased specification
Number of temp files created_tmp_files Files/second Instance Number of temp files created per second
Number of opened tables opened_tables - Instance Number of opened tables
Number of commits com_commit Commits/second Instance Number of commits per second
Number of rollbacks com_rollback Rollback/second Instance Number of rollbacks per second
Number of created threads threads_created - Instance Number of threads created to process connections
Number of running threads threads_running - Instance Number of active (non-idle) threads
Maximum number of connections max_connections - Instance Maximum number of connections
Number of temp disk tables created_tmp_disk_tables Tables/second Instance Number of temp disk tables created per second
Number of requests to read the next row handler_read_rnd_next Requests/second Instance Number of requests to read the next row per second
Number of internal rollbacks handler_rollback Rollbacks/second Instance Number of transaction rollbacks per second
Number of internal commits handler_commit Commits/second Instance Number of transaction commits per second
Number of empty InnoDB pages innodb_buffer_pool_pages_free - Instance Number of empty memory pages in the InnoDB engine
Total number of InnoDB pages innodb_buffer_pool_pages_total - Instance Total number of memory pages occupied by the InnoDB engine
InnoDB logical reads innodb_buffer_pool_read_requests Reads/second Instance Number for logical read requests completed by the InnoDB engine per second
Number of InnoDB physical reads innodb_buffer_pool_reads Reads/second Instance Number for physical read requests completed by the InnoDB engine per second
Amount of data read by InnoDB innodb_data_read Bytes/s Instance Number of bytes read by the InnoDB engine per second
Total number of InnoDB reads innodb_data_reads Reads/second Instance Number of data reads completed by the InnoDB engine per second
Total number of InnoDB writes innodb_data_writes Writes/second Instance Number of data writes completed by the InnoDB engine per second
Amount of data written by InnoDB innodb_data_written Bytes/s Instance Number of bytes written by the InnoDB engine per second
Number of rows deleted by InnoDB innodb_rows_deleted Rows/second Instance Number of rows deleted by the InnoDB engine per second
Number of rows inserted by InnoDB innodb_rows_inserted Rows/second Instance Number of rows inserted by the InnoDB engine per second
Number of rows updated by InnoDB innodb_rows_updated Rows/second Instance Number of rows updated by the InnoDB engine per second
Number of rows read by InnoDB innodb_rows_read Rows/second Instance Number of rows read by the InnoDB engine per second
Average time of row lock in InnoDB innodb_row_lock_time_avg Milliseconds Instance Average time of row lock in the InnoDB engine
Number of row locks waited by InnoDB innodb_row_lock_waits Locks/second Instance Number of row locks waited by the InnoDB engine per second
Number of unused blocks in the key cache key_blocks_unused - Instance Number of unused blocks in the key cache in the MyISAM engine
Number of used blocks in the key cache key_blocks_used - Instance Number of used blocks in the key cache in the MyISAM engine
Number of block reads from the key cache key_read_requests Reads/second Instance Number of block reads from the key cache by the MyISAM engine per second
Number of block reads from the disk key_read Reads/second Instance Number of block reads from the disk by the MyISAM engine per second
Number of block writes to the key cache key_write_requests Writes/second Instance Number of block writes to the key cache by the MyISAM engine per second
Number of block writes to the disk key_write_requests Writes/second Instance Number of block writes to the disk by the MyISAM engine per second
Master-slave delay distance master_slave_sync_distance MB Instance Master-slave binlog delay
Master-slave delay time seconds_behind_master Seconds Instance Master-slave delay time
IO thread status slave_io_running Status value (0: yes, 1: no, 2: connecting) Instance IO thread status
SQL thread status slave_sql_running Status value (0: yes, 1: no) Instance SQL thread status

For more information on how to use TencentDB monitoring metrics, see the TencentDB for MySQL APIs in Cloud Monitor.