MatrixOne System Databases and Tables

MatrixOne system databases and tables are where MatrixOne stores system information, allowing you to access system details through them. During initialization, MatrixOne Intelligence creates 5 system databases: mo_catalog, information_schema, system_metrics, system, and mysql. System databases and tables are default internal system components, and users can only perform read operations on them.

---

mo_catalog Database

mo_catalog is used to store metadata for MatrixOne objects, such as databases, tables, columns, system variables, tenants, users, and roles.

mo_indexes Table

Column Attribute	Type	Description
id	BIGINT UNSIGNED(64)	Index ID
table_id	BIGINT UNSIGNED(64)	ID of the table where the index is located
database_id	BIGINT UNSIGNED(64)	ID of the database where the index is located
name	VARCHAR(64)	Name of the index
type	VARCHAR(11)	Type of index, including primary key index (PRIMARY), unique index (UNIQUE), secondary index (MULTIPLE)
algo	VARCHAR(11)	Algorithm used to create the index
algo_table_type	VARCHAR(11)	Hidden table type for multi-table indexes
algo_params	VARCHAR(2048)	Index algorithm parameters
is_visible	TINYINT(8)	Whether the index is visible, 1 for visible, 0 for invisible (currently all MatrixOne indexes are visible)
hidden	TINYINT(8)	Whether the index is hidden, 1 for hidden, 0 for not hidden
comment	VARCHAR(2048)	Comment for the index
column_name	VARCHAR(256)	Column name of the index's constituent column
ordinal_position	INT UNSIGNED(32)	Column sequence in the index, starting from 1
options	TEXT(0)	Options information for the index
index_table_name	VARCHAR(5000)	Table name of the index table corresponding to this index, currently only unique indexes have index tables

mo_table_partitions Table

Column Attribute	Type	Description
table_id	BIGINT UNSIGNED(64)	ID of the current partitioned table
database_id	BIGINT UNSIGNED(64)	ID of the database to which the current partitioned table belongs
number	SMALLINT UNSIGNED(16)	Current partition number. All partitions are indexed in the order they are defined, where 1 is the number assigned to the first partition.
name	VARCHAR(64)	Name of the partition
partition_type	VARCHAR(50)	Stores the partition type information of the table. If it is a partitioned table, its enumerated values are "KEY", "LINEAR_KEY", "HASH", "LINEAR_KEY_51", "RANGE", "RANGE_COLUMNS", "LIST", "LIST_COLUMNS"; if it is not a partitioned table, the value of partition_type is an empty string.Note: MatrixOne currently does not support RANGE and LIST partitions.
partition_expression	VARCHAR(2048)	The partition function expression used in the CREATE TABLE or ALTER TABLE statement when creating the partitioned table.
description_utf8	TEXT(0)	This column is used for RANGE and LIST partitions. For RANGE partitions, it contains the value set in the partition's VALUES LESS THAN clause, which can be an integer or MAXVALUE. For LIST partitions, this column contains the values defined in the partition's values in clause, which is a comma-separated list of integer values. For partitions that are not RANGE or LIST, this column is always NULL.Note: MatrixOne currently does not support RANGE and LIST partitions, so this column is NULL.
comment	VARCHAR(2048)	The text of the comment. Otherwise, this value is empty.
options	TEXT(0)	Options information for the partition, currently NULL
partition_table_name	VARCHAR(1024)	Name of the partition sub-table corresponding to the current partition

mo_user Table

Column Attribute	Type	Description
user_id	int	User ID, primary key
user_host	varchar(100)	User host address
user_name	varchar(100)	Username
authentication_string	varchar(100)	Encrypted authentication string for the password
status	varchar(8)	Enabled, locked, invalid
created_time	timestamp	User creation time
expired_time	timestamp	User expiration time
login_type	varchar(16)	ssl/password/other
creator	int	ID of the creator who created this user
owner	int	Administrator ID of this user
default_role	int	Default role ID for this user

mo_database Table

Column Attribute	Type	Description
dat_id	bigint unsigned	Primary key ID
datname	varchar(100)	Database name
dat_catalog_name	varchar(100)	Database catalog name, default def
dat_createsql	varchar(100)	SQL statement for creating the database
owner	int unsigned	Role ID
creator	int unsigned	User ID
created_time	timestamp	Creation time
account_id	int unsigned	Tenant ID
dat_type	varchar(23)	Database type, normal database or subscription database

mo_role Table

Column Attribute	Type	Description
role_id	int unsigned	Role ID, primary key
role_name	varchar(100)	Role name
creator	int unsigned	User ID
owner	int unsigned	MatrixOne Administrator/Tenant Administrator Owner ID
created_time	timestamp	Creation time
comments	text	Comments

mo_user_grant Table

Column Attribute	Type	Description
role_id	int unsigned	Authorized role ID, composite primary key
user_id	int unsigned	User ID of the user granted the role, composite primary key
granted_time	timestamp	Grant time
with_grant_option	bool	Whether the authorized user is allowed to authorize other users or roles

mo_role_grant Table

Column Attribute	Type	Description
granted_id	int	ID of the role being granted, composite primary key
grantee_id	int	ID of the role to be granted to other roles, composite primary key
operation_role_id	int	Operation role ID
operation_user_id	int	Operation user ID
granted_time	timestamp	Grant time
with_grant_option	bool	Whether the authorized role is allowed to authorize other users or roles

mo_role_privs Table

Column Attribute	Type	Description
role_id	int unsigned	Role ID, composite primary key
role_name	varchar(100)	Role name: accountadmin/public
obj_type	varchar(16)	Object type: account/database/table, composite primary key
obj_id	bigint unsigned	Object ID, composite primary key
privilege_id	int	Privilege ID, composite primary key
privilege_name	varchar(100)	Privilege name: list of privileges
privilege_level	varchar(100)	Privilege level, composite primary key
operation_user_id	int unsigned	Operation user ID
granted_time	timestamp	Grant time
with_grant_option	bool	Whether authorization is allowed

mo_user_defined_function Table

Column Attribute	Type	Description
function_id	INT(32)	ID of the function, primary key
name	VARCHAR(100)	Name of the function
owner	INT UNSIGNED(32)	Role ID of the creator of the function
args	TEXT(0)	Parameter list of the function
rettype	VARCHAR(20)	Return type of the function
body	TEXT(0)	Function body of the function
language	VARCHAR(20)	Language used by the function
db	VARCHAR(100)	Database where the function is located
definer	VARCHAR(50)	Name of the user who defined the function
modified_time	TIMESTAMP(0)	Last modification time of the function
created_time	TIMESTAMP(0)	Creation time of the function
type	VARCHAR(10)	Type of the function, default FUNCTION
security_type	VARCHAR(10)	Security handling method, uniform value DEFINER
comment	VARCHAR(5000)	Comments for creating the function
character_set_client	VARCHAR(64)	Client character set: utf8mb4
collation_connection	VARCHAR(64)	Connection collation: utf8mb4_0900_ai_ci
database_collation	VARCHAR(64)	Database connection collation: utf8mb4_0900_ai_ci

mo_mysql_compatibility_mode Table

Column Attribute	Type	Description
configuration_id	INT(32)	Configuration item ID, auto-incrementing column, serving as the primary key to distinguish different configurations
account_id	INT(32)	Tenant ID where the configuration is located
account_name	VARCHAR(300)	Tenant name where the configuration is located
dat_name	VARCHAR(5000)	Database name where the configuration is located
variable_name	VARCHAR(300)	Name of the variable
variable_value	VARCHAR(5000)	Value of the variable
system_variables	BOOL(0)	Whether it is a system variable (in addition to system variables, compatibility variables are also added)

mo_pubs Table

Column Attribute	Type	Description
pub_name	VARCHAR(64)	Publication name
database_name	VARCHAR(5000)	Name of the published database
database_id	BIGINT UNSIGNED(64)	ID of the published database, corresponding to dat_id in the mo_database table
all_table	BOOL(0)	Whether the published database includes all tables within the database corresponding to database_id
table_list	TEXT(0)	When not all_table, a list of tables included in the published database, where table names correspond one-to-one with tables under the database corresponding to database_id
account_list	TEXT(0)	When not all_account, a list of accounts allowed to subscribe to this published database
created_time	TIMESTAMP(0)	Time when the published database was created
owner	INT UNSIGNED(32)	Role ID corresponding to the creation of the published database
creator	INT UNSIGNED(32)	User ID corresponding to the creation of the published database
comment	TEXT(0)	Remarks for creating the published database

mo_stages Table

Column Attribute	Type	Description
stage_id	INT UNSIGNED(32)	Data stage ID
stage_name	VARCHAR(64)	Data stage name
url	TEXT(0)	Object storage path (without authentication), file system path
stage_credentials	TEXT(0)	Authentication information, saved after encryption
stage_status	VARCHAR(64)	ENABLED/DISABLED Default: DISABLED
created_time	TIMESTAMP(0)	Creation time
comment	TEXT(0)	Comment

mo_sessions View

Column Name	Data Type	Description
node_id	VARCHAR(65535)	Unique identifier for a MatrixOne node. Cannot be changed once started.
conn_id	INT UNSIGNED	Unique number related to the client TCP connection in MatrixOne, automatically generated by Hakeeper.
session_id	VARCHAR(65535)	Unique UUID to identify the session. A new UUID is generated for each new session.
account	VARCHAR(65535)	Name of the tenant.
user	VARCHAR(65535)	Name of the user.
host	VARCHAR(65535)	IP address and port of the CN node receiving client requests.
db	VARCHAR(65535)	Name of the database used when executing SQL.
session_start	VARCHAR(65535)	Timestamp when the session was created.
command	VARCHAR(65535)	Type of MySQL command, such as COM_QUERY, COM_STMT_PREPARE, COM_STMT_EXECUTE, etc.
info	VARCHAR(65535)	SQL statement being executed. An SQL statement may contain multiple statements.
txn_id	VARCHAR(65535)	Unique identifier of the related transaction.
statement_id	VARCHAR(65535)	Unique identifier (UUID) of the SQL statement.
statement_type	VARCHAR(65535)	Type of the SQL statement, such as SELECT, INSERT, UPDATE, etc.
query_type	VARCHAR(65535)	Kind of SQL statement, such as DQL (Data Query Language), TCL (Transaction Control Language), etc.
sql_source_type	VARCHAR(65535)	Source of the SQL statement, such as external or internal.
query_start	VARCHAR(65535)	Timestamp when the SQL statement started execution.
client_host	VARCHAR(65535)	IP address and port number of the client.
role	VARCHAR(65535)	Role name of the user.

mo_configurations View

Column Name	Data Type	Description
node_type	VARCHAR(65535)	Type of the node: cn (compute node), tn (transaction node), log (log node), proxy (proxy).
node_id	VARCHAR(65535)	Unique identifier of the node.
name	VARCHAR(65535)	Name of the configuration item, possibly with a nested structure prefix.
current_value	VARCHAR(65535)	Current value of the configuration item.
default_value	VARCHAR(65535)	Default value of the configuration item.
internal	VARCHAR(65535)	Indicates whether the configuration parameter is an internal parameter.

mo_locks View

Column Name	Data Type	Description
cn_id	VARCHAR(65535)	UUID of the CN node.
txn_id	VARCHAR(65535)	Transaction holding the lock.
table_id	VARCHAR(65535)	Table being locked.
lock_key	VARCHAR(65535)	Lock type. Can be point or range.
lock_content	VARCHAR(65535)	Content of the lock, represented in hexadecimal. For range locks, it represents an interval; for point locks, it represents a single value.
lock_mode	VARCHAR(65535)	Lock mode. Can be shared or exclusive.
lock_status	VARCHAR(65535)	Lock status, can be wait, acquired, or none.\<br>wait: No transaction holds the lock, but there are transactions waiting on the lock.\<br>acquired: A transaction holds the lock.\<br>none: No transaction holds the lock, and no transactions are waiting on the lock.
lock_wait	VARCHAR(65535)	Transactions waiting on this lock.

mo_variables View

Column Name	Data Type	Description
configuration_id	INT(32)	Auto-incrementing column, used to uniquely identify each configuration item.
account_id	INT(32)	Unique identifier of the tenant.
account_name	VARCHAR(300)	Name of the tenant.
dat_name	VARCHAR(5000)	Name of the database.
variable_name	VARCHAR(300)	Name of the configuration variable.
variable_value	VARCHAR(5000)	Value of the configuration variable.
system_variables	BOOL(0)	Indicates whether the configuration variable is a system-level variable.

mo_transactions View

Column Name	Data Type	Description
cn_id	VARCHAR(65535)	Unique ID of the CN (Compute Node).
txn_id	VARCHAR(65535)	Unique ID of the transaction.
create_ts	VARCHAR(65535)	Timestamp of transaction creation, following RFC3339Nano format ("2006-01-02T15:04:05.999999999Z07:00").
snapshot_ts	VARCHAR(65535)	Represents the transaction's snapshot timestamp, expressed as physical and logical time.
prepared_ts	VARCHAR(65535)	Represents the transaction's prepared timestamp, expressed as physical and logical time.
commit_ts	VARCHAR(65535)	Represents the transaction's commit timestamp, expressed as physical and logical time.
txn_mode	VARCHAR(65535)	Identifies the transaction mode, can be pessimistic or optimistic.
isolation	VARCHAR(65535)	Represents the transaction's isolation level, can be SI (Snapshot Isolation) or RC (Read Committed).
user_txn	VARCHAR(65535)	Indicates a user transaction, i.e., a transaction created by a user connecting to MatrixOne via a client and performing SQL operations.
txn_status	VARCHAR(65535)	Represents the current status of the transaction. Possible values include active, committed, aborting, aborted. In distributed transaction 2PC mode, it will also include prepared and committing.
table_id	VARCHAR(65535)	Represents the ID of the table involved in the transaction.
lock_key	VARCHAR(65535)	Represents the type of lock, can be range or point.
lock_content	VARCHAR(65535)	For point locks, it represents a single value; for range locks, it represents a range, usually in the "low - high" format. Note that a transaction may involve multiple locks, but only the first lock is displayed here.
lock_mode	VARCHAR(65535)	Represents the mode of the lock, can be exclusive or shared.

mo_columns Table

Column Attribute	Type	Description
att_uniq_name	varchar(256)	Primary key. Hidden composite primary key, format similar to "${att_relname_id}-${attname}"
account_id	int unsigned	Tenant ID
att_database_id	bigint unsigned	Database ID
att_database	varchar(256)	Database Name
att_relname_id	bigint unsigned	Table ID
att_relname	varchar(256)	The table to which this column belongs. (Refer to mo_tables.relname)
attname	varchar(256)	Column name
atttyp	varchar(256)	Data type of this column (deleted columns are 0).
attnum	int	Column number. Regular columns are numbered starting from 1.
att_length	int	Byte size of the type
attnotnull	tinyint(1)	Indicates a not-null constraint.
atthasdef	tinyint(1)	This column has a default expression or generated expression.
att_default	varchar(1024)	Default expression
attisdropped	tinyint(1)	This column has been dropped and is no longer valid. Dropped columns physically still exist in the table, but the parser ignores them, so they cannot be accessed via SQL.
att_constraint_type	char(1)	p = Primary key constraint\<br>n = No constraint
att_is_unsigned	tinyint(1)	Whether it is unsigned
att_is_auto_increment	tinyint(1)	Whether it is auto-increment
att_comment	varchar(1024)	Comment
att_is_hidden	tinyint(1)	Whether it is hidden
attr_has_update	tinyint(1)	This column contains an update expression
attr_update	varchar(1024)	Update expression
attr_is_clusterby	tinyint(1)	Whether this column is used as a cluster by keyword to create the table
attr_seqnum	SMALLINT UNSIGNED(0)	Sequence number for each column
attr_enum	varchar(65535)	If the type of this column is ENUM, it represents the ENUM type value represented by this column, otherwise it is empty.

mo_tables Table

Column Attribute	Type	Description
rel_id	bigint unsigned	Primary key, Table ID
relname	varchar(100)	Name of table, index, view, etc.
reldatabase	varchar(100)	Database containing this relation, refer to mo_database.datname
reldatabase_id	bigint unsigned	ID of the database containing this relation, refer to mo_database.datid
relpersistence	varchar(100)	p = Permanent table\<br> t = Temporary table
relkind	varchar(100)	r = Ordinary table\<br> e = External table\<br> i = Index\<br> S = Sequence\<br> v = View\<br> m = Materialized view
rel_comment	varchar(100)	Table comment
rel_createsql	varchar(100)	SQL statement for creating the table
created_time	timestamp	Creation time
creator	int unsigned	Creator ID
owner	int unsigned	Creator's default role ID
account_id	int unsigned	Tenant ID
partitioned	blob	Partitioned by statement
partition_info	blob	Partition information
viewdef	blob	View definition statement
constraint	varchar(5000)	Constraints associated with the table
rel_version	INT UNSIGNED(0)	Primary key, table version number
catalog_version	INT UNSIGNED(0)	System table version number

---

system_metrics Database

system_metrics collects status and statistical information on SQL statements, CPU, and memory resource usage.

Some common column types in metrics tables, with descriptions as follows:

-collecttime: Collection time. -value: Collected metrics value. -node: UUID of the MatrixOne node. -role: MatrixOne node role, including CN, TN, and Log. -account: Defaults to the "sys" tenant, which is the account that triggered the SQL request. -type: SQL type, can be select, insert, update, delete, or other type.

metric Table

Column Attribute	Type	Description
metric_name	VARCHAR(128)	Metric name, e.g., sql_statement_total, server_connections, process_cpu_percent, sys_memory_used, etc.
collecttime	DATETIME	Metric data collection time
value	DOUBLE	Metric value
node	VARCHAR(36)	MatrixOne node UUID
role	VARCHAR(32)	MatrixOne node role
account	VARCHAR(128)	Tenant name, default sys
type	VARCHAR(32)	SQL type, e.g., INSERT, SELECT, UPDATE

The following tables are views of the metric table:

• sql_statement_total table: Counter for executed SQL statements.
• sql_statement_errors table: Counter for SQL statements that encountered errors.
• sql_transaction_total table: Counter for transactional SQL statements.
• sql_transaction_errors table: Counter for transaction statements that executed with errors.
• server_connections table: Number of server connections.
• server_storage_usage: Server storage usage.
• process_cpu_percent table: Percentage of CPU process busyness.
• process_resident_memory_bytes table: Amount of resident memory, in bytes.
• process_open_fds table: Number of open file descriptors.
• sys_cpu_seconds_total table: Total system CPU time, in seconds, normalized by core count.
• sys_cpu_combined_percent table: System CPU busyness percentage, average of all logical cores.
• sys_memory_used table: Used system memory in bytes.
• sys_memory_available table: Available system memory in bytes.
• sys_disk_read_bytes table: System disk read in bytes.
• sys_disk_write_bytes table: System disk write in bytes.
• sys_net_recv_bytes table: System network received in bytes.
• sys_net_sent_bytes table: System network sent in bytes.

---

system Database

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

statement_info Table

The statement_info table records user and system SQL statements and their detailed information.

Column Attribute	Type	Description
statement_id	VARCHAR(36)	Unique ID of the statement
transaction_id	VARCHAR(36)	Unique ID of the transaction
session_id	VARCHAR(36)	Unique ID of the account
account	VARCHAR(1024)	Tenant name
user	VARCHAR(1024)	User name
host	VARCHAR(1024)	User client IP
database	VARCHAR(1024)	Current database where the session is active
statement	TEXT	SQL statement
statement_tag	TEXT	Comment tag in the statement (reserved)
statement_fingerprint	TEXT	Comment tag in the statement (reserved)
node_uuid	VARCHAR(36)	Node UUID, i.e., the node that generated the data
node_type	VARCHAR(64)	Node type within MatrixOne, belonging to TN/CN/Log
request_at	DATETIME	Datetime when the request was accepted
response_at	DATETIME	Datetime when the response was sent
duration	BIGINT	Execution time, unit: ns
status	VARCHAR(32)	SQL statement execution status: Running, Success, Failed
err_code	VARCHAR(1024)	Error code
error	TEXT	Error message
exec_plan	JSON	Statement execution plan
rows_read	BIGINT	Total rows read
bytes_scan	BIGINT	Total bytes scanned
stats	JSON	Global statistics from exec_plan
statement_type	VARCHAR(1024)	Statement type: [Insert, Delete, Update, Drop Table, Drop User, ...]
query_type	VARCHAR(1024)	Query type: [DQL, DDL, DML, DCL, TCL]
role_id	BIGINT	Role ID
sql_source_type	TEXT	SQL statement source type: internal_sql, external_sql, cloud_nonuser_sql
result_count	BIGINT(64)	Number of rows in SQL execution result
aggr_count	BIGINT(64)	Number of aggregations

rawlog Table

The rawlog table records very detailed system logs.

Column Attribute	Type	Description
raw_item	VARCHAR(1024)	Original log item
node_uuid	VARCHAR(36)	Node UUID, i.e., the node that generated the data
node_type	VARCHAR(64)	Node type within MatrixOne, belonging to TN/CN/Log
span_id	VARCHAR(16)	Unique ID of the span
trace_id	VARCHAR(36)	Unique trace UUID
logger_name	VARCHAR(1024)	Name of the logger
timestamp	DATETIME	Timestamp of the action
level	VARCHAR(1024)	Log level, e.g., debug, info, warn, error, panic, fatal
caller	VARCHAR(1024)	Location where the log was generated: package/file.go:123
message	TEXT	Log message
extra	JSON	Dynamic fields of the log
err_code	VARCHAR(1024)	Error log
error	TEXT	Error message
stack	VARCHAR(4096)	Stack information for log_info and error_info
span_name	VARCHAR(1024)	Span name, e.g., step name of execution plan, function name in code, ...
parent_span_id	VARCHAR(16)	Unique ID of the parent span
start_time	DATETIME	Start time of the span
end_time	DATETIME	End time of the span
duration	BIGINT	Execution time, unit: ns
resource	JSON	Static resource information
span_kind	VARCHAR(1024)	Span type. internal: MO internal generated trace (default); statement: trace_id==statement_id; remote: communication via morpc
statement_id	VARCHAR(36)	ID of the statement
session_id	VARCHAR(36)	ID of the session

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

---

information_schema Database

Information Schema provides an ANSI standard way to view system metadata. In addition to tables included for MySQL compatibility, MatrixOne also provides many custom information_schema tables.

Many INFORMATION_SCHEMA tables have corresponding SHOW commands. Querying INFORMATION_SCHEMA allows joins between tables.

MySQL Compatibility Tables

Table Name	Description
KEY_COLUMN_USAGE	Describes key constraints on columns, such as primary key constraints.
COLUMNS	Provides a list of columns for all tables.
PROFILING	Provides some analysis information when SQL statements are executed.
PROCESSLIST	Provides information similar to executing the SHOW PROCESSLIST command.
USER_PRIVILEGES	Lists privileges associated with the current user.
SCHEMATA	Provides information similar to executing SHOW DATABASES.
CHARACTER_SETS	Provides a list of character sets supported by the server.
TRIGGERS	Provides information similar to executing SHOW TRIGGERS.
TABLES	Provides a list of tables visible to the current user. Similar to executing SHOW TABLES.
PARTITIONS	Provides partition information for tables.
VIEWS	Provides information about views in the database.
ENGINES	Provides a list of supported storage engines.
ROUTINES	Provides some information about stored procedures.
PARAMETERS	Provides information about parameters and return values of stored procedures.
KEYWORDS	Provides information about keywords in the database. See Keywords for details.

CHARACTER_SETS Table

The columns in the CHARACTER_SETS table are described as follows:

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

COLUMNS View

The columns in the COLUMNS view are described as follows:

• TABLE_CATALOG: The name of the catalog to which the table containing this column belongs. This value is always def.
• TABLE_SCHEMA: The name of the schema where the table containing the column is located.
• TABLE_NAME: The name of the table containing the column.
• COLUMN_NAME: The name of the column.
• ORDINAL_POSITION: The position of the column in the table.
• COLUMN_DEFAULT: The default value for the column. This value is NULL if the explicit default value is NULL, or if the column definition does not contain a default clause.
• IS_NULLABLE: Whether the column can be nullable. The value is YES if the column can store null values; otherwise, it is NO.
• DATA_TYPE: The data type 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: Numeric precision for numeric type columns.
• NUMERIC_SCALE: Numeric scale for numeric type columns.
• DATETIME_PRECISION: For time type columns, fractional seconds precision.
• CHARACTER_SET_NAME: Character set name for string columns.
• COLLATION_NAME: Name of the collation for string columns.
• COLUMN_TYPE: Column type.
• COLUMN_KEY: Whether this column is indexed. This field can 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 a primary key or one of multiple primary keys.
  • UNI: This column is the first column of a unique index.
  • MUL: This column is the first column of a non-unique index, where a given value is allowed to appear multiple times.
• EXTRA: Any additional information for the given column.
• PRIVILEGES: Privileges that the current user has on this column.
• COLUMN_COMMENT: Description included in the column definition.
• GENERATION_EXPRESSION: For generated columns, this value shows the expression used to calculate the column value. For non-generated columns, this value is empty.
• SRS_ID: This value applies to spatial columns. It contains the column's SRID value, which indicates a spatial reference system for values stored in that column.

ENGINES Table

The columns in the ENGINES table are described as follows:

• ENGINE: The name of the storage engine.
• SUPPORT: The server's level of support for the storage engine.
• COMMENT: A short 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.

PARTITIONS View

The columns in the PARTITIONS view are described as follows:

• TABLE_CATALOG: The name of the catalog to which the table containing this column belongs. This value is always def.
• TABLE_SCHEMA: The name of the schema where the table containing the column is located.
• TABLE_NAME: The name of the table containing the column.
• PARTITION_NAME: The name of the partition.
• SUBPARTITION_NAME: If the row in the PARTITIONS table represents a subpartition, this is the name of that subpartition; otherwise, it is empty.
• PARTITION_ORDINAL_POSITION: All partitions are indexed in the order they are defined, where 1 is the number assigned to the first partition. As partitions are added, deleted, and reorganized, the index may change; the number displayed in this column reflects the current order, taking into account any index changes.
• SUBPARTITION_ORDINAL_POSITION: Within a given partition, subpartitions are indexed and re-indexed in the same way as partitions within a table.
• PARTITION_METHOD: One of RANGE, LIST, HASH, LINEAR HASH, KEY, or LINEAR KEY.Note: MatrixOne currently does not support RANGE and LIST partitions.
• SUBPARTITION_METHOD: One of HASH, LINEAR HASH, KEY, or LINEAR KEY.
• PARTITION_EXPRESSION: The partition function expression used in the CREATE TABLE or ALTER TABLE statement when creating the table's current partitioning scheme.
• SUBPARTITION_EXPRESSION: This is similar to PARTITION_EXPRESSION, used to define how the table is subpartitioned. If the table has no subpartitions, this column is empty.
• PARTITION_DESCRIPTION: This column applies to RANGE and LIST partitions. For RANGE partitions, it contains the value set in the partition's VALUES LESS THAN clause, which can be an integer or MAXVALUE. For LIST partitions, this column contains the values defined in the partition's VALUES IN clause, which is a comma-separated set of integer values. For partitions whose PARTITION_METHOD is not RANGE or LIST, this column is always empty.Note: MatrixOne currently does not support RANGE and LIST partitions.
• TABLE_ROWS: The number of table rows in the partition.
• AVG_ROW_LENGTH: The average length of rows stored in this partition or subpartition, in bytes. This is the same as the result of DATA_LENGTH divided by TABLE_ROWS.
• DATA_LENGTH: The total length of all rows stored in this partition or subpartition, in bytes; i.e., the total number of bytes stored in the partition or subpartition.
• MAX_DATA_LENGTH: Maximum data length of the partition.
• INDEX_LENGTH: The length of the index file for this partition or subpartition, in bytes.
• DATA_FREE: The number of bytes allocated to the partition or subpartition but not used.
• CREATE_TIME: The time the partition or subpartition was created.
• UPDATE_TIME: The time the partition or subpartition was last modified.
• CHECK_TIME: The time the table belonging to this partition or subpartition was last checked.
• CHECKSUM: The checksum value, if any; otherwise, it is empty.
• PARTITION_COMMENT: If the partition has a comment, this is the text of the comment. If not, the value is empty. The maximum length for partition comments is defined as 1024 characters, and the display width of the PARTITION_COMMENT column is also 1024 characters to match this limit.
• NODEGROUP: The node group to which this partition belongs.
• TABLESPACE_NAME: The name of the tablespace to which this partition belongs. This value is always DEFAULT.

PROCESSLIST View

The fields in the PROCESSLIST view are described as follows:

• NODE_ID: CN node UUID.
• CONN_ID: User connection ID.
• SESSION_ID: Session ID.
• ACCOUNT: Tenant name.
• USER: User name.
• HOST: CN node listening address.
• DB: Current connected database.
• SESSION_START: Session creation time.
• COMMAND: MySQL protocol Command of the statement.
• INFO: SQL statement being processed.
• TXN_ID: Transaction ID.
• STATEMENT_ID: Statement ID.
• STATEMENT_TYPE: Statement type, e.g., Select/Update/Delete.
• QUERY_TYPE: Query type, e.g., DQL/DDL/DML.
• SQL_SOURCE_TYPE: SQL statement source type, external or internal SQL: external_sql/internal_sql.
• QUERY_START: Query start time.
• CLIENT_HOST: Client address.

SCHEMATA View

The SCHEMATA view provides information about databases, with data equivalent to the result of the SHOW DATABASES statement. The fields in the SCHEMATA view are described as follows:

• CATALOG_NAME: The catalog to which the database belongs.
• SCHEMA_NAME: The name of the database.
• 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 the database and general tablespaces.

TABLES View

The columns in the TABLES view are described as follows:

• TABLE_CATALOG: The name of the catalog to which the table belongs. This value is always def.
• TABLE_SCHEMA: The name of the schema to which the table belongs.
• TABLE_NAME: The name of the table.
• TABLE_TYPE: The type of the table. Basic table type is BASE TABLE, view table type is VIEW, and INFORMATION_SCHEMA table type is SYSTEM VIEW.
• ENGINE: The type of storage engine.
• VERSION: Version. Default value is 10.
• ROW_FORMAT: Row storage format. Values are Fixed, Dynamic, Compressed, Redundant, Compact.
• TABLE_ROWS: Number of rows in the table. For INFORMATION_SCHEMA tables, TABLE_ROWS is NULL.
• AVG_ROW_LENGTH: Average row length of the table. AVG_ROW_LENGTH = DATA_LENGTH / TABLE_ROWS.
• DATA_LENGTH: Data length. DATA_LENGTH = TABLE_ROWS * sum of stored lengths of columns in tuples.
• MAX_DATA_LENGTH: Maximum data length. This value is currently 0, indicating no upper limit on data length.
• INDEX_LENGTH: Index length. INDEX_LENGTH = TABLE_ROWS * total length of columns in index tuples.
• DATA_FREE: Data fragment. This value is currently 0.
• AUTO_INCREMENT: Current step of the auto-increment primary key.
• CREATE_TIME: Time when the table was created.
• UPDATE_TIME: Time when the table was updated.
• CHECK_TIME: Time when the table was checked.
• TABLE_COLLATION: Collation of strings in the table.
• CHECKSUM: Checksum.
• CREATE_OPTIONS: Creation options.
• TABLE_COMMENT: Table comments and remarks.

USER_PRIVILEGES Table

The USER_PRIVILEGES table provides information about global privileges.

The fields in the USER_PRIVILEGES table are described as follows:

• GRANTEE: The authorized username, in the format 'user_name'@'host_name'.
• TABLE_CATALOG: The name of the catalog to which the table belongs. The value is def.
• PRIVILEGE_TYPE: The type of privilege to be granted. Each row displays only one privilege type.
• IS_GRANTABLE: If you have the GRANT OPTION privilege, the value is YES; otherwise, the value is NO.

VIEWS View

• TABLE_CATALOG: The name of the catalog to which the view belongs. The value is def.
• TABLE_SCHEMA: The name of the database to which the view belongs.
• TABLE_NAME: The name of the view.
• VIEW_DEFINITION: Provides the SELECT statement that defines the view. This includes most of what is seen in theCreate Table column generated by SHOW Create VIEW.
• CHECK_OPTION: The value of the CHECK_OPTION attribute. Values are NONE, CASCADE, or LOCAL.
• IS_UPDATABLE: When CREATE VIEW is set, a flag named view updatability flag is set. If UPDATE and DELETE (and similar operations) are legal for the view, the flag is set to YES (true). Otherwise, the flag is set to NO (false).
• DEFINER: The account of the user who created the view, in the format username@hostname.
• SECURITY_TYPE: The SQL SECURITY characteristic of the view. Values are DEFINER or INVOKER.
• CHARACTER_SET_CLIENT: The session value of the character_set_client system variable when the view was created.
• COLLATION_CONNECTION: The session value of the collation_connection system variable when the view was created.
• INDEX_COMMENT: Any comments provided for indexes with the comment attribute when the index was created.
• IS_VISIBLE: Indicates whether the index is visible to the optimizer. Currently, this field has no meaning in MO.
• EXPRESSION: Represents an expression or function in the index. Currently, this field has no meaning in MO.

STATISTICS View

Get detailed information about database table indexes and statistics. For example, you can check if an index is unique, understand the column order in an index, and estimate the number of unique values in an index.

• TABLE_CATALOG: The catalog name of the table (always 'def').
• TABLE_SCHEMA: The database name to which the table belongs.
• TABLE_NAME: The name of the table.
• NON_UNIQUE: Indicates whether the index allows duplicate values. If 0, the index is unique.
• INDEX_SCHEMA: The database name to which the index belongs.
• INDEX_NAME: The name of the index.
• SEQ_IN_INDEX: The position of the column in the index.
• COLUMN_NAME: The name of the column.
• COLLATION: The collation of the column.
• CARDINALITY: An estimate of the number of unique values in the index.
• SUB_PART: The length of the index part. For the entire column, this value is NULL.
• PACKED: Indicates whether compressed values are used for storage.
• NULLABLE: Indicates whether the column allows NULL values.
• INDEX_TYPE: The type of index (e.g., BTREE, HASH, etc.).
• COMMENT: Comment information for the index.
• INDEX_COMMENT: Any comments provided for indexes with the comment attribute when the index was created.
• IS_VISIBLE: Indicates whether the index is visible to the optimizer. Currently, this field has no meaning in MO.
• EXPRESSION: Represents an expression or function in the index. Currently, this field has no meaning in MO.

mysql Database

Authorization System Tables

The authorization system tables contain 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: Privileges for stored procedures and stored functions.