Performance_Schema Database

TDengine includes a built-in database named PERFORMANCE_SCHEMA to provide access to database performance statistics. This document introduces the tables of PERFORMANCE_SCHEMA and their structure.

PERF_APP

Provides information about clients (such as applications) that connect to the cluster. Similar to SHOW APPS.

#	Column	Data Type	Description
1	app_id	UBIGINT	Client ID
2	ip	BINARY(16)	Client IP address
3	pid	INT	Client process
4	name	BINARY(24)	Client name
5	start_time	TIMESTAMP	Time when client was started
6	insert_req	UBIGINT	Insert requests
7	insert_row	UBIGINT	Rows inserted
8	insert_time	UBIGINT	Time spent processing insert requests in microseconds
9	insert_bytes	UBIGINT	Size of data inserted in byted
10	fetch_bytes	UBIGINT	Size of query results in bytes
11	query_time	UBIGINT	Time spend processing query requests
12	slow_query	UBIGINT	Number of slow queries (greater than or equal to 3 seconds)
13	total_req	UBIGINT	Total requests
14	current_req	UBIGINT	Requests currently being processed
15	last_access	TIMESTAMP	Last update time

PERF_CONNECTIONS

Provides information about connections to the database. Similar to SHOW CONNECTIONS.

#	Column	Data Type	Description
1	conn_id	INT	Connection ID
2	user	BINARY(24)	User name
3	app	BINARY(24)	Client name
4	pid	UINT	Client process ID on client device that initiated the connection
5	end_point	BINARY(128)	Client endpoint
6	login_time	TIMESTAMP	Login time
7	last_access	TIMESTAMP	Last update time

PERF_QUERIES

Provides information about SQL queries currently running. Similar to SHOW QUERIES.

#	Column	Data Type	Description
1	kill_id	UBIGINT	ID used to stop the query
2	query_id	INT	Query ID
3	conn_id	UINT	Connection ID
4	app	BINARY(24)	Client name
5	pid	INT	Client process ID on client device
6	user	BINARY(24)	User name
7	end_point	BINARY(16)	Client endpoint
8	create_time	TIMESTAMP	Creation time
9	exec_usec	BIGINT	Elapsed time
10	stable_query	BOOL	Whether the query is on a supertable
11	sub_num	INT	Number of subqueries
12	sub_status	BINARY(1000)	Subquery status
13	sql	BINARY(1024)	SQL statement

PERF_CONSUMERS

#	Column	Data Type	Description
1	consumer_id	BIGINT	Consumer ID
2	consumer_group	BINARY(192)	Consumer group
3	client_id	BINARY(192)	Client ID (user-defined)
4	status	BINARY(20)	Consumer status. All possible status include: ready(consumer is in normal state), lost(the connection between consumer and mnode is broken), rebalance(the redistribution of vgroups that belongs to current consumer is now in progress), unknown(consumer is in invalid state)
5	topics	BINARY(204)	Subscribed topic. Returns one row for each topic.
6	up_time	TIMESTAMP	Time of first connection to TDengine Server
7	subscribe_time	TIMESTAMP	Time of first subscription
8	rebalance_time	TIMESTAMP	Time of first rebalance triggering

PERF_TRANS

#	Column	Data Type	Description
1	id	INT	ID of the transaction currently running
2	create_time	TIMESTAMP	Creation time
3	stage	BINARY(12)	Transaction stage (redoAction, undoAction, or commit)
4	db1	BINARY(64)	First database having a conflict with the transaction
5	db2	BINARY(64)	Second database having a conflict with the transaction
6	failed_times	INT	Times the transaction has failed
7	last_exec_time	TIMESTAMP	Previous time the transaction was run
8	last_action_info	BINARY(511)	Reason for failure on previous run

PERF_SMAS

#	Column	Data Type	Description
1	sma_name	BINARY(192)	Time-range-wise SMA name
2	create_time	TIMESTAMP	Creation time
3	stable_name	BINARY(192)	Supertable name
4	vgroup_id	INT	Dedicated vgroup name