User Statistics
The User Statistics (userstat) plugin creates the USER_STATISTICS, CLIENT_STATISTICS, the INDEX_STATISTICS, and the TABLE_STATISTICS tables in the INFORMATION_SCHEMA database. As an alternative to these tables, the plugin also adds the SHOW USER_STATISTICS, the SHOW CLIENT_STATISTICS, the SHOW INDEX_STATISTICS, and the SHOW TABLE_STATISTICS statements.
These tables and commands can be used to understand the server activity better and to identify the sources of your database's load.
The plugin also adds the FLUSH USER_STATISTICS, FLUSH CLIENT_STATISTICS, FLUSH INDEX_STATISTICS, and FLUSH TABLE_STATISTICS statements.
The MariaDB implementation of this plugin is based on the userstatv2 patch from Percona and Ourdelta. The original code comes from Google (Mark Callaghan's team) with additional work from Percona, Ourdelta, and Weldon Whipple. The MariaDB implementation provides the same functionality as the userstatv2 patch but a lot of changes have been made to make it faster and to better fit the MariaDB infrastructure.
Contents
How it Works
The userstat
plugin works by keeping several hash tables in memory. All variables are incremented while the query is running. At the end of each statement the global values are updated.
Enabling the Plugin
By default statistics are not collected. This is to ensure that statistics collection does not cause any extra load on the server unless desired.
Set the userstat=ON system variable in a relevant server option group in an option file to enable the plugin. For example:
[mariadb] ... userstat = 1
The value can also be changed dynamically. For example:
SET GLOBAL userstat=1;
Using the Plugin
Using the Information Schema Table
The userstat
plugin creates the USER_STATISTICS, CLIENT_STATISTICS, the INDEX_STATISTICS, and the TABLE_STATISTICS tables in the INFORMATION_SCHEMA database.
SELECT * FROM INFORMATION_SCHEMA.USER_STATISTICS\G *************************** 1. row *************************** USER: root TOTAL_CONNECTIONS: 1 CONCURRENT_CONNECTIONS: 0 CONNECTED_TIME: 297 BUSY_TIME: 0.001725 CPU_TIME: 0.001982 BYTES_RECEIVED: 388 BYTES_SENT: 2327 BINLOG_BYTES_WRITTEN: 0 ROWS_READ: 0 ROWS_SENT: 12 ROWS_DELETED: 0 ROWS_INSERTED: 13 ROWS_UPDATED: 0 SELECT_COMMANDS: 4 UPDATE_COMMANDS: 0 OTHER_COMMANDS: 3 COMMIT_TRANSACTIONS: 0 ROLLBACK_TRANSACTIONS: 0 DENIED_CONNECTIONS: 0 LOST_CONNECTIONS: 0 ACCESS_DENIED: 0 EMPTY_QUERIES: 1
SELECT * FROM INFORMATION_SCHEMA.CLIENT_STATISTICS\G *************************** 1. row *************************** CLIENT: localhost TOTAL_CONNECTIONS: 3 CONCURRENT_CONNECTIONS: 0 CONNECTED_TIME: 4883 BUSY_TIME: 0.009722 CPU_TIME: 0.0102131 BYTES_RECEIVED: 841 BYTES_SENT: 13897 BINLOG_BYTES_WRITTEN: 0 ROWS_READ: 0 ROWS_SENT: 214 ROWS_DELETED: 0 ROWS_INSERTED: 207 ROWS_UPDATED: 0 SELECT_COMMANDS: 10 UPDATE_COMMANDS: 0 OTHER_COMMANDS: 13 COMMIT_TRANSACTIONS: 0 ROLLBACK_TRANSACTIONS: 0 DENIED_CONNECTIONS: 0 LOST_CONNECTIONS: 0 ACCESS_DENIED: 0 EMPTY_QUERIES: 1 1 row in set (0.00 sec)
SELECT * FROM INFORMATION_SCHEMA.INDEX_STATISTICS WHERE TABLE_NAME = "author"; +--------------+------------+------------+-----------+ | TABLE_SCHEMA | TABLE_NAME | INDEX_NAME | ROWS_READ | +--------------+------------+------------+-----------+ | books | author | by_name | 15 | +--------------+------------+------------+-----------+
SELECT * FROM INFORMATION_SCHEMA.TABLE_STATISTICS WHERE TABLE_NAME='user'; +--------------+------------+-----------+--------------+------------------------+ | TABLE_SCHEMA | TABLE_NAME | ROWS_READ | ROWS_CHANGED | ROWS_CHANGED_X_INDEXES | +--------------+------------+-----------+--------------+------------------------+ | mysql | user | 5 | 2 | 2 | +--------------+------------+-----------+--------------+------------------------+
Using the SHOW Statements
As an alternative to the INFORMATION_SCHEMA tables, the userstat
plugin also adds the SHOW USER_STATISTICS, the SHOW CLIENT_STATISTICS, the SHOW INDEX_STATISTICS, and the SHOW TABLE_STATISTICS statements.
These commands are another way to display the information stored in the information schema tables. WHERE clauses are accepted. LIKE clauses are accepted but ignored.
SHOW USER_STATISTICS SHOW CLIENT_STATISTICS SHOW INDEX_STATISTICS SHOW TABLE_STATISTICS
Flushing Plugin Data
The userstat
plugin also adds the FLUSH USER_STATISTICS, FLUSH CLIENT_STATISTICS, FLUSH INDEX_STATISTICS, and FLUSH TABLE_STATISTICS statements, which discard the information stored in the specified information schema table.
FLUSH USER_STATISTICS FLUSH CLIENT_STATISTICS FLUSH INDEX_STATISTICS FLUSH TABLE_STATISTICS
Versions
USER_STATISTICS
Version | Status | Introduced |
---|---|---|
2.0 | Stable | MariaDB 10.1.18 |
2.0 | Gamma | MariaDB 10.1.1 |
CLIENT_STATISTICS
Version | Status | Introduced |
---|---|---|
2.0 | Stable | MariaDB 10.1.13 |
2.0 | Gamma | MariaDB 10.1.1 |
INDEX_STATISTICS
Version | Status | Introduced |
---|---|---|
2.0 | Stable | MariaDB 10.1.13 |
2.0 | Gamma | MariaDB 10.1.1 |
TABLE_STATISTICS
Version | Status | Introduced |
---|---|---|
2.0 | Stable | MariaDB 10.1.18 |
2.0 | Gamma | MariaDB 10.1.1 |
System Variables
userstat
- Description: If set to
1
, user statistics will be activated. - Commandline:
--userstat=1
- Scope: Global
- Dynamic: Yes
- Data Type:
boolean
- Default Value:
OFF
Status Variables
User Statistics introduced a number of new status variables:
- access_denied_errors
- binlog_bytes_written
- busy_time (requires userstat to be set to be recorded)
- cpu_time (requires userstat to be set to be recorded)
- empty_queries
- rows_read
- rows_sent