Aurora MySQL–specific information_schema tables

Aurora MySQL has certain information_schema tables that are specific to Aurora.

information_schema.aurora_global_db_instance_status

The information_schema.aurora_global_db_instance_status table contains information about the status of all DB instances in a global database's primary and secondary DB clusters. The following table shows the columns that you can use. The remaining columns are for Aurora internal use only.

Note

This information schema table is only available with Aurora MySQL version 3.04.0 and higher global databases.

Column	Data type	Description
SERVER_ID	varchar(100)	The identifier of the DB instance.
SESSION_ID	varchar(100)	A unique identifier for the current session. A value of MASTER_SESSION_ID identifies the Writer (primary) DB instance.
AWS_REGION	varchar(100)	The AWS Region in which this global database instance runs. For a list of Regions, see Region availability.
DURABLE_LSN	bigint unsigned	The log sequence number (LSN) made durable in storage. A log sequence number (LSN) is a unique sequential number that identifies a record in the database transaction log. LSNs are ordered such that a larger LSN represents a later transaction.
HIGHEST_LSN_RCVD	bigint unsigned	The highest LSN received by the DB instance from the writer DB instance.
OLDEST_READ_VIEW_TRX_ID	bigint unsigned	The ID of the oldest transaction that the writer DB instance can purge to.
OLDEST_READ_VIEW_LSN	bigint unsigned	The oldest LSN used by the DB instance to read from storage.
VISIBILITY_LAG_IN_MSEC	float(10,0) unsigned	For readers in the primary DB cluster, how far this DB instance is lagging behind the writer DB instance in milliseconds. For readers in a secondary DB cluster, how far this DB instance is lagging behind the secondary volume in milliseconds.

information_schema.aurora_global_db_status

The information_schema.aurora_global_db_status table contains information about various aspects of Aurora global database lag, specifically, lag of the underlying Aurora storage (so called durability lag) and lag between the recovery point objective (RPO). The following table shows the columns that you can use. The remaining columns are for Aurora internal use only.

Note

This information schema table is only available with Aurora MySQL version 3.04.0 and higher global databases.

Column	Data type	Description
AWS_REGION	varchar(100)	The AWS Region in which this global database instance runs. For a list of Regions, see Region availability.
HIGHEST_LSN_WRITTEN	bigint unsigned	The highest log sequence number (LSN) that currently exists on this DB cluster. A log sequence number (LSN) is a unique sequential number that identifies a record in the database transaction log. LSNs are ordered such that a larger LSN represents a later transaction.
DURABILITY_LAG_IN_MILLISECONDS	float(10,0) unsigned	The difference in the timestamp values between the HIGHEST_LSN_WRITTEN on a secondary DB cluster and the HIGHEST_LSN_WRITTEN on the primary DB cluster. This value is always 0 on the primary DB cluster of the Aurora global database.
RPO_LAG_IN_MILLISECONDS	float(10,0) unsigned	The recovery point objective (RPO) lag. The RPO lag is the time it takes for the most recent user transaction COMMIT to be stored on a secondary DB cluster after it's been stored on the primary DB cluster of the Aurora global database. This value is always 0 on the primary DB cluster of the Aurora global database. In simple terms, this metric calculates the recovery point objective for each Aurora MySQL DB cluster in the Aurora global database, that is, how much data might be lost if there were an outage. As with lag, RPO is measured in time.
LAST_LAG_CALCULATION_TIMESTAMP	datetime	The timestamp that specifies when values were last calculated for DURABILITY_LAG_IN_MILLISECONDS and RPO_LAG_IN_MILLISECONDS. A time value such as 1970-01-01 00:00:00+00 means this is the primary DB cluster.
OLDEST_READ_VIEW_TRX_ID	bigint unsigned	The ID of the oldest transaction that the writer DB instance can purge to.

information_schema.replica_host_status

The information_schema.replica_host_status table contains replication information. The columns that you can use are shown in the following table. The remaining columns are for Aurora internal use only.

Column	Data type	Description
CPU	double	The CPU percentage usage of the replica host.
IS_CURRENT	tinyint	Whether the replica is current.
LAST_UPDATE_TIMESTAMP	datetime(6)	The time the last update occurred. Used to determine whether a record is stale.
REPLICA_LAG_IN_MILLISECONDS	double	The replica lag in milliseconds.
SERVER_ID	varchar(100)	The ID of the database server.
SESSION_ID	varchar(100)	The ID of the database session. Used to determine whether a DB instance is a writer or reader instance.

Note

When a replica instance falls behind, the information queried from its information_schema.replica_host_status table might be outdated. In this situation, we recommend that you query from the writer instance instead.

While the mysql.ro_replica_status table has similar information, we don't recommend that you use it.

information_schema.aurora_forwarding_processlist

The information_schema.aurora_forwarding_processlist table contains information about processes involved in write forwarding.

The contents of this table are visible only on the writer DB instance for a DB cluster with global or in-cluster write forwarding turned on. An empty result set is returned on reader DB instances.

Field	Data type	Description
ID	bigint	The identifier of the connection on the writer DB instance. This identifier is the same value displayed in the Id column of the SHOW PROCESSLIST statement and returned by the CONNECTION_ID() function within the thread.
USER	varchar(32)	The MySQL user that issued the statement.
HOST	varchar(255)	The MySQL client that issued the statement. For forwarded statements, this field shows the application client host address that established the connection on the forwarding reader DB instance.
DB	varchar(64)	The default database for the thread.
COMMAND	varchar(16)	The type of command the thread is executing on behalf of the client, or Sleep if the session is idle. For descriptions of thread commands, see the MySQL documentation on Thread Command Values in the MySQL documentation.
TIME	int	The time in seconds that the thread has been in its current state.
STATE	varchar(64)	An action, event, or state that indicates what the thread is doing. For descriptions of state values, see General Thread States in the MySQL documentation.
INFO	longtext	The statement that the thread is executing, or NULL if it isn't executing a statement. The statement might be the one sent to the server, or an innermost statement if the statement executes other statements.
IS_FORWARDED	bigint	Indicates whether the thread is forwarded from a reader DB instance.
REPLICA_SESSION_ID	bigint	The connection identifier on the Aurora Replica. This identifier is the same value displayed in the Id column of the SHOW PROCESSLIST statement on the forwarding Aurora reader DB instance.
REPLICA_INSTANCE_IDENTIFIER	varchar(64)	The DB instance identifier of the forwarding thread.
REPLICA_CLUSTER_NAME	varchar(64)	The DB cluster identifier of the forwarding thread. For in-cluster write forwarding, this identifier is the same DB cluster as the writer DB instance.
REPLICA_REGION	varchar(64)	The AWS Region from which the forwarding thread originates. For in-cluster write forwarding, this Region is the same AWS Region as the writer DB instance.