MatrixOne System Database and Tables

MatrixOne system database and tables are where MatrixOne stores system information. We can access the system information through them. MatrixOne creates 6 system databases at initialization: mo_catalog, information_schema, system_metrcis, system, mysql, and mo_task. mo_task is under development and have no direct impact on users. The other system databases and table functions are described in this document.

The system can only modify system databases and tables, and users can only read from them.

mo_catalog database

mo_catalog stores the metadata of MatrixOne objects: databases, tables, columns, system variables, accounts, users, and roles.

Start with MatrixOne 0.6 has introduced the concept of multi-account, the default sys account and other accounts have slightly different behaviors. The system table mo_account, which serves the multi-tenancy management, is only visible for the sys account; the other accounts don't see this table.

mo_database table

column	type	comments
dat_id	bigint unsigned	Primary key
datname	varchar(100)	Database name
dat_catalog_name	varchar(100)	Database catalog name, default as def
dat_createsql	varchar(100)	Database creation SQL statement
owner	int unsigned	Role id
creator	int unsigned	User id
created_time	timestamp	Create time
account_id	int unsigned	Account id

mo_tables table

column	type	comments
rel_id	bigint unsigned	Primary key
relname	varchar(100)	Name of the table, index, view, and so on.
reldatabase	varchar(100)	The database that contains this relation. reference mo_database.datname
reldatabase_id	bigint unsigned	The database id that contains this relation. reference mo_database.datid
relpersistence	varchar(100)	p = permanent table, t = temporary table
relkind	varchar(100)	r = ordinary table, e = external table, i = index, S = sequence, v = view, m = materialized view
rel_comment	varchar(100)
rel_createsql	varchar(100)	Table creation SQL statement
created_time	timestamp	Create time
creator	int unsigned	Creator ID
owner	int unsigned	Creator's default role id
account_id	int unsigned	Account id
partitioned	blob	Partition by statement
viewdef	blob	View definition statement

mo_columns table

column	type	comments
att_uniq_name	varchar(256)	Primary Key. Hidden, composite primary key, format is like "${att_relname_id}-${attname}"
account_id	int unsigned	accountID
att_database_id	bigint unsigned	databaseID
att_database	varchar(256)	database Name
att_relname_id	bigint unsigned	table id
att_relname	varchar(256)	The table this column belongs to.(references mo_tables.relname)
attname	varchar(256)	The column name
atttyp	varchar(256)	The data type of this column (zero for a dropped column).
attnum	int	The number of the column. Ordinary columns are numbered from 1 up.
att_length	int	bytes count for the type.
attnotnull	tinyint(1)	This represents a not-null constraint.
atthasdef	tinyint(1)	This column has a default expression or generation expression.
att_default	varchar(1024)	default expression
attisdropped	tinyint(1)	This column has been dropped and is no longer valid. A dropped column is still physically present in the table, but is ignored by the parser and so cannot be accessed via SQL.
att_constraint_type	char(1)	p = primary key constraint, n=no constraint
att_is_unsigned	tinyint(1)	unsigned or not
att_is_auto_increment	tinyint(1)	auto increment or not
att_comment	varchar(1024)	comment
att_is_hidden	tinyint(1)	hidden or not
attr_has_update	tinyint(1)	This columns has update expression
attr_update	varchar(1024)	update expression

mo_account table (Only visible for sys account)

column	type	comments
account_id	int unsigned	account id
account_name	varchar(100)	account name
status	varchar(100)	open/suspend
created_time	timestamp	create time
comments	varchar(256)	comment
suspended_time	TIMESTAMP	Time of the account's status is changed

mo_role table

column	type	comments
role_id	int unsigned	role id
role_name	varchar(100)	role name
creator	int unsigned	user_id
owner	int unsigned	MOADMIN/ACCOUNTADMIN ownerid
created_time	timestamp	create time
comments	text	comment

mo_user table

column	type	comments
user_id	int	user id
user_host	varchar(100)	user host address
user_name	varchar(100)	user name
authentication_string	varchar(100)	authentication string encrypted with password
status	varchar(8)	open,locked,expired
created_time	timestamp	user created time
expired_time	timestamp	user expired time
login_type	varchar(16)	ssl/password/other
creator	int	the creator id who created this user
owner	int	the admin id for this user
default_role	int	the default role id for this user

mo_user_grant table

column	type	comments
role_id	int unsigned	role id
user_id	int unsigned	user id
granted_time	timestamp	granted time
with_grant_option	bool	If permission granting is permitted

mo_role_grant table

column	type	comments
granted_id	int	the role id being granted
grantee_id	int	the role id to grant others
operation_role_id	int	operation role id
operation_user_id	int	operation user id
granted_time	timestamp	granted time
with_grant_option	bool	If permission granting is permitted

mo_role_privs table

column	type	comments
role_id	int	role id
role_name	varchar(100)	role name: accountadmin/public
obj_type	varchar(16)	object type: account/database/table
obj_id	bigint unsigned	object id
privilege_id	int	privilege id
privilege_name	varchar(100)	privilege name: the list of privileges
privilege_level	varchar(100)	level of privileges
operation_user_id	int unsigned	operation user id
granted_time	timestamp	granted time
with_grant_option	bool	If permission granting is permitted

system_metrics database

system_metrics collect the status and statistics of SQL statements, CPU & memory resource usage.

system_metrics tables have more or less same column types, fields in these tables are described as follows:

• collecttime:Collection time

• value: the value of the collecting metric

• node: the MatrixOne node uuid

• role: the MatrixOne node role, can be CN, DN or LOG.
• account: default as "sys", the account who fires the SQL request.
• type:SQL type, can be select, insert, update, delete, other types.

metric table

Column	Type	Comment
metric_name	VARCHAR(128)	metric name, like: sql_statement_total, server_connections, process_cpu_percent, sys_memory_used, ..
collecttime	DATETIME	metric data collect time
value	DOUBLE	metric value
node	VARCHAR(36)	MatrixOne node uuid
role	VARCHAR(32)	MatrixOne node role
account	VARCHAR(128)	account name, default "sys"
type	VARCHAR(32)	SQL type: like insert, select, update ...

The other tables are all views of the metric table:

• process_cpu_percent table: Process CPU busy percentage.
• process_open_fs table: Number of open file descriptors.
• process_resident_memory_bytes table: Resident memory size in bytes.
• server_connection table: Server connection numbers.
• sql_statement_errors table: Counter of sql statements executed with errors.
• sql_statement_total table: Counter of executed sql statement.
• sql_transaction_errors table: Counter of transactional statements executed with errors.
• sql_transaction_total table: Counter of transactional sql statement.
• sys_cpu_combined_percent table: System CPU busy percentage, average among all logical cores.
• sys_cpu_seconds_total table: System CPU time spent in seconds, normalized by number of cores
• sys_disk_read_bytes table: System disk read in bytes.
• sys_disk_write_bytes table: System disk write in bytes.
• sys_memory_available table: System memory available in bytes.
• sys_memory_used table: System memory used in bytes.
• sys_net_recv_bytes table: System net received in bytes.
• sys_net_sent_bytes table: System net sent in bytes.

system database

System database stores MatrixOne historical SQL statements, system logs, error information.

statement_info table

It records user and system SQL statement with detailed information.

Column	Type	Comments
statement_id	VARCHAR(36)	statement unique id
transaction_id	VARCHAR(36)	Transaction unique id
session_id	VARCHAR(36)	session unique id
account	VARCHAR(1024)	account name
user	VARCHAR(1024)	user name
host	VARCHAR(1024)	user client ip
database	VARCHAR(1024)	what database current session stay in
statement	TEXT	sql statement
statement_tag	TEXT	note tag in statement(Reserved)
statement_fingerprint	TEXT	note tag in statement(Reserved)
node_uuid	VARCHAR(36)	node uuid, which node gen this data
node_type	VARCHAR(64)	node type in MO, val in [DN, CN, LOG]
request_at	DATETIME	request accept datetime
response_at	DATETIME	response send datetime
duration	BIGINT	exec time, unit: ns
status	VARCHAR(32)	sql statement running status, enum: Running, Success, Failed
err_code	VARCHAR(1024)	error code
error	TEXT	error message
exec_plan	JSON	statement execution plan
rows_read	BIGINT	rows read total
bytes_scan	BIGINT	bytes scan total
stats	JSON	global stats info in exec_plan
statement_type	VARCHAR(1024)	statement type, val in [Insert, Delete, Update, Drop Table, Drop User, ...]
query_type	VARCHAR(1024)	query type, val in [DQL, DDL, DML, DCL, TCL]
role_id	BIGINT	role id
sql_source_type	TEXT	Type of SQL source internally generated by MatrixOne

rawlog table

It records very detailed system logs.

Column	Type	Comments
raw_item	VARCHAR(1024)	raw log item
node_uuid	VARCHAR(36)	node uuid, which node gen this data.
node_type	VARCHAR(64)	node type in MO, val in [DN, CN, LOG]
span_id	VARCHAR(16)	span unique id
statement_id	VARCHAR(36)	statement unique id
logger_name	VARCHAR(1024)	logger name
timestamp	DATETIME	timestamp of action
level	VARCHAR(1024)	log level, enum: debug, info, warn, error, panic, fatal
caller	VARCHAR(1024)	where it log, like: package/file.go:123
message	TEXT	log message
extra	JSON	log dynamic fields
err_code	VARCHAR(1024)	error log
error	TEXT	error message
stack	VARCHAR(4096)
span_name	VARCHAR(1024)	span name, for example: step name of execution plan, function name in code, ...
parent_span_id	VARCHAR(16)	parent span unique id
start_time	DATETIME
end_time	DATETIME
duration	BIGINT	exec time, unit: ns
resource	JSON	static resource information

The other 3 tables(log_info, span_info and error_info) are views of statement_info and rawlog table.

information_schema database

Information Schema provides an ANSI-standard way of viewing system metadata. MatrixOne also provides a number of custom information_schema tables, in addition to the tables included for MySQL compatibility.

Many INFORMATION_SCHEMA tables have a corresponding SHOW command. The benefit of querying INFORMATION_SCHEMA is that it is possible to join between tables.

Tables for MySQL compatibility

Table Name	Description
CHARACTER_SETS	Provides a list of character sets the server supports.
COLUMNS	Provides a list of columns for all tables.
ENGINES	Provides a list of supported storage engines.
KEY_COLUMN_USAGE	Describes the key constraints of the columns, such as the primary key constraint.
PROCESSLIST	Provides similar information to the command SHOW PROCESSLIST.
SCHEMATA	Provides similar information to SHOW DATABASES.
TABLES	Provides a list of tables that the current user has visibility of. Similar to SHOW TABLES.
TRIGGERS	Provides similar information to SHOW TRIGGERS.
USER_PRIVILEGES	Summarizes the privileges associated with the current user.

CHARACTER_SETS table

The description of columns in the CHARACTER_SETS table is as follows:

• CHARACTER_SET_NAME: The name of the character set.
• DEFAULT_COLLATE_NAME The default collation name of the character set.
• DESCRIPTION The description of the character set.
• MAXLEN The maximum length required to store a character in this character set.

COLUMNS table

The description of columns in the COLUMNS table is as follows:

• TABLE_CATALOG: The name of the catalog to which the table with the column belongs. The value is always def.
• TABLE_SCHEMA: The name of the schema in which the table with the column is located.
• TABLE_NAME: The name of the table with the column.
• COLUMN_NAME: The name of the column.
• ORDINAL_POSITION: The position of the column in the table.
• COLUMN_DEFAULT: The default value of the column. If the explicit default value is NULL, or if the column definition does not include the default clause, this value is NULL.
• IS_NULLABLE: Whether the column is nullable. If the column can store null values, this value is YES; otherwise, it is NO.
• DATA_TYPE: The type of data in the column.
• CHARACTER_MAXIMUM_LENGTH: For string columns, the maximum length in characters.
• CHARACTER_OCTET_LENGTH: For string columns, the maximum length in bytes.
• NUMERIC_PRECISION: The numeric precision of a number-type column.
• NUMERIC_SCALE: The numeric scale of a number-type column.
• DATETIME_PRECISION: For time-type columns, the fractional seconds precision.
• CHARACTER_SET_NAME: The name of the character set of a string column.
• COLLATION_NAME: The name of the collation of a string column.
• COLUMN_TYPE: The column type.
• COLUMN_KEY: Whether this column is indexed. This field might have the following values:
• Empty: This column is not indexed, or this column is indexed and is the second column in a multi-column non-unique index.
• PRI: This column is the primary key or one of multiple primary keys.
• UNI: This column is the first column of the unique index.
• MUL: The column is the first column of a non-unique index, in which a given value is allowed to occur for multiple times.
• EXTRA: Any additional information of the given column.
• PRIVILEGES: The privilege that the current user has on this column.
• COLUMN_COMMENT: Comments contained in the column definition.
• GENERATION_EXPRESSION: For generated columns, this value displays the expression used to calculate the column value. For non-generated columns, the value is empty.
• SRS_ID: This value applies to spatial columns. It contains the column SRID value that indicates the spatial reference system for values stored in the column.

ENGINES table

The description of columns in the ENGINES table is as follows:

• ENGINES: The name of the storage engine.
• SUPPORT: The level of support that the server has on the storage engine.
• COMMENT: The brief comment on the storage engine.
• TRANSACTIONS: Whether the storage engine supports transactions.
• XA: Whether the storage engine supports XA transactions.
• SAVEPOINTS: Whether the storage engine supports savepoints.

PROCESSLIST table

Fields in the PROCESSLIST table are described as follows:

• ID: The ID of the user connection.
• USER: The name of the user who is executing PROCESS.
• HOST: The address that the user is connecting to.
• DB: The name of the currently connected default database.
• COMMAND: The command type that PROCESS is executing.
• TIME: The current execution duration of PROCESS, in seconds.
• STATE: The current connection state.
• INFO: The requested statement that is being processed.

SCHEMATA table

The SCHEMATA table provides information about databases. The table data is equivalent to the result of the SHOW DATABASES statement. Fields in the SCHEMATA table are described as follows:

• CATALOG_NAME: The catalog to which the database belongs.
• SCHEMA_NAME: The database name.
• DEFAULT_CHARACTER_SET_NAME: The default character set of the database.
• DEFAULT_COLLATION_NAME: The default collation of the database.
• SQL_PATH: The value of this item is always NULL.
• DEFAULT_TABLE_ENCRYPTION: defines the default encryption setting for databases and general tablespaces.

TABLES table

The description of columns in the TABLES table is as follows:

• TABLE_CATALOG: The name of the catalog which the table belongs to. The value is always def.
• TABLE_SCHEMA: The name of the schema which the table belongs to.
• TABLE_NAME: The name of the table.
• TABLE_TYPE: The type of the table.
• ENGINE: The type of the storage engine.
• VERSION: Version. The value is 10 by default.
• ROW_FORMAT: The row format. The value is currently Compact.
• TABLE_ROWS: The number of rows in the table in statistics.
• AVG_ROW_LENGTH: The average row length of the table. AVG_ROW_LENGTH = DATA_LENGTH / TABLE_ROWS.
• DATA_LENGTH: Data length. DATA_LENGTH = TABLE_ROWS * the sum of storage lengths of the columns in the tuple. The replicas of TiKV are not taken into account.
• MAX_DATA_LENGTH: The maximum data length. The value is currently 0, which means the data length has no upper limit.
• INDEX_LENGTH: The index length. INDEX_LENGTH = TABLE_ROWS * the sum of lengths of the columns in the index tuple.
• DATA_FREE: Data fragment. The value is currently 0.
• AUTO_INCREMENT: The current step of the auto- increment primary key.
• CREATE_TIME: The time at which the table is created.
• UPDATE_TIME: The time at which the table is updated.
• CHECK_TIME: The time at which the table is checked.
• TABLE_COLLATION: The collation of strings in the table.
• CHECKSUM: Checksum.
• CREATE_OPTIONS: Creates options.
• TABLE_COMMENT: The comments and notes of the table.

USER_PRIVILEGES table

The USER_PRIVILEGES table provides information about global privileges.

Fields in the USER_PRIVILEGES table are described as follows:

• GRANTEE: The name of the granted user, which is in the format of 'user_name'@'host_name'.
• TABLE_CATALOG: The name of the catalog to which the table belongs. This value is always def.
• PRIVILEGE_TYPE: The privilege type to be granted. Only one privilege type is shown in each row.
• IS_GRANTABLE: If you have the GRANT OPTION privilege, the value is YES; otherwise, the value is NO.

mysql database

Grant system tables

These system tables contain grant information about user accounts and their privileges:

• user: user accounts, global privileges, and other non-privilege columns.
• db: database-level privileges.
• tables_priv: table-level privileges.
• columns_priv: column-level privileges.
• procs_priv: stored procedure and stored function privileges.