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Amazon CloudWatch
User Guide

Amazon RDS Metrics and Dimensions

Amazon Relational Database Service sends metrics to CloudWatch for each active database instance every minute. Detailed monitoring is enabled by default. For more information, see Monitoring a DB Instance in the Amazon Relational Database Service User Guide.

Amazon RDS Metrics

The AWS/RDS namespace includes the following metrics.

Metric Description
BinLogDiskUsage

The amount of disk space occupied by binary logs on the master. Applies to MySQL read replicas.

Units: Bytes

BufferCacheHitRatio

The percentage of requests that are served by the buffer cache.

Units: Bytes

BurstBalance

The percent of General Purpose SSD (gp2) burst-bucket I/O credits available.

Units: Percent

CPUUtilization

The percentage of CPU utilization.

Units: Percent

CPUCreditUsage

[T2 instances] The number of CPU credits used by the instance for CPU utilization. One CPU credit equals one vCPU running at 100% utilization for one minute or an equivalent combination of vCPUs, utilization, and time (for example, one vCPU running at 50% utilization for two minutes or two vCPUs running at 25% utilization for two minutes).

CPU credit metrics are available at a five-minute frequency only. If you specify a period greater than five minutes, use the Sum statistic instead of the Average statistic.

Units: Credits (vCPU-minutes)

CPUCreditBalance

[T2 instances] The number of earned CPU credits accumulated since the instance was launched, less the credits used, up to a maximum number based on the instance size.

Credits are stored in the credit balance after they are earned, and removed from the credit balance when they are used. The credit balance has a maximum limit, determined by the instance size. If the credit balance has reached the limit, additional earned credits are not added to the balance.

The credits in the CPUCreditBalance are available for the instance to use to burst beyond its baseline CPU utilization.

Credits on a running instance do not expire. However, if you stop an instance, it loses all the credits in the credit balance.

CPU credit metrics are available at a five-minute frequency only.

Units: Credits (vCPU-minutes)

CPUSurplusCreditBalance

[T2 instances] The number of surplus credits that have been used by a T2 Unlimited instance when its CPUCreditBalance is zero.

The CPUSurplusCreditBalance is paid down by earned CPU credits.

Units: Credits (vCPU-minutes)

CPUSurplusCreditsCharged

[T2 instances] The number of surplus credits that have been used by a T2 Unlimited instance that are not offset by earned CPU credits. CPUSurplusCreditsCharged tracks the surplus credits that incur an additional charge, and represents the difference between CPUSurplusCreditBalance and CPUCreditBalance.

Units: Credits (vCPU-minutes)

DatabaseConnections

The number of database connections in use.

Units: Count

DiskQueueDepth

The number of outstanding IOs (read/write requests) waiting to access the disk.

Units: Count

FreeableMemory

The amount of available random access memory.

Units: Bytes

FreeStorageSpace

The amount of available storage space.

Units: Bytes

MaximumUsedTransactionIDs

The maximum transaction ID that has been used. Applies to PostgreSQL.

Units: Count

NetworkReceiveThroughput

The incoming (Receive) network traffic on the DB instance, including both customer database traffic and Amazon RDS traffic used for monitoring and replication.

Units: Bytes/second

NetworkTransmitThroughput

The outgoing (Transmit) network traffic on the DB instance, including both customer database traffic and Amazon RDS traffic used for monitoring and replication.

Units: Bytes/second

OldestReplicationSlotLag

The lagging size of the replica lagging the most in terms of WAL data received. Applies to PostgreSQL.

Units: Megabytes

ReadIOPS

The average number of disk I/O operations per second during the polling period.

Units: Count/Second

ReadLatency

The average amount of time taken per disk I/O operation.

Units: Seconds

ReadThroughput

The average number of bytes read from disk per second.

Units: Bytes/Second

ReplicaLag

The amount of time a Read Replica DB instance lags behind the source DB instance. Applies to MySQL, MariaDB, and PostgreSQL Read Replicas.

Units: Seconds

ReplicationSlotDiskUsage

The disk space used by replication slot files. Applies to PostgreSQL.

Units: Megabytes

SwapUsage

The amount of swap space used on the DB instance.

Units: Bytes

TransactionLogsDiskUsage

The disk space used by transaction logs. Applies to PostgreSQL.

Units: Megabytes

TransactionLogsGeneration

The size of transaction logs generated per second. Applies to PostgreSQL.

Units: Megabytes/second

WriteIOPS

The average number of disk I/O operations per second.

Units: Count/Second

WriteLatency

The average amount of time taken per disk I/O operation.

Units: Seconds

WriteThroughput

The average number of bytes written to disk per second.

Units: Bytes/Second

Amazon Aurora Metrics

The AWS/RDS namespace includes the following metrics that apply to database entities running on Amazon Aurora.

Metric Description

ActiveTransactions

The average number of current transactions executing on an Aurora database instance per second.

AuroraBinlogReplicaLag

The amount of time a replica DB cluster running on Aurora with MySQL compatibility lags behind the source DB cluster.

This metric reports the value of the Seconds_Behind_Master field of the MySQL SHOW SLAVE STATUS command. This metric is useful for monitoring replica lag between Aurora DB clusters that are replicating across different AWS Regions. For more information, see Aurora MySQL Replication.

AuroraReplicaLag

For an Aurora Replica, the amount of lag when replicating updates from the primary instance, in milliseconds.

AuroraReplicaLagMaximum

The maximum amount of lag between the primary instance and each Aurora DB instance in the DB cluster, in milliseconds.

AuroraReplicaLagMinimum

The minimum amount of lag between the primary instance and each Aurora DB instance in the DB cluster, in milliseconds.

BinLogDiskUsage

The amount of disk space occupied by binary logs on the master, in bytes.

BlockedTransactions

The average number of transactions in the database that are blocked per second.

BufferCacheHitRatio

The percentage of requests that are served by the buffer cache.

CommitLatency

The amount of latency for commit operations, in milliseconds.

CommitThroughput

The average number of commit operations per second.

CPUCreditBalance

The number of CPU credits that an instance has accumulated. This metric applies only to db.t2.small and db.t2.medium instances. It is used to determine how long an Aurora MySQL DB instance can burst beyond its baseline performance level at a given rate.

Note

CPU credit metrics are reported at 5-minute intervals.

CPUCreditUsage

The number of CPU credits consumed during the specified period. This metric applies only to db.t2.small and db.t2.medium instances. It identifies the amount of time during which physical CPUs have been used for processing instructions by virtual CPUs allocated to the Aurora MySQL DB instance.

Note

CPU credit metrics are reported at 5-minute intervals.

CPUUtilization

The percentage of CPU used by an Aurora DB instance.

DatabaseConnections

The number of connections to an Aurora DB instance.

DDLLatency

The amount of latency for data definition language (DDL) requests, in milliseconds—for example, create, alter, and drop requests.

DDLThroughput

The average number of DDL requests per second.

Deadlocks

The average number of deadlocks in the database per second.

DeleteLatency

The amount of latency for delete queries, in milliseconds.

DeleteThroughput

The average number of delete queries per second.

DiskQueueDepth

The number of outstanding read/write requests waiting to access the disk.

DMLLatency

The amount of latency for inserts, updates, and deletes, in milliseconds.

DMLThroughput

The average number of inserts, updates, and deletes per second.

EngineUptime

The amount of time that the instance has been running, in seconds.

FreeableMemory

The amount of available random access memory, in bytes.

FreeLocalStorage

The amount of storage available for temporary tables and logs, in bytes.

Unlike for other DB engines, for Aurora DB instances this metric reports the amount of storage available to each DB instance for temporary tables and logs. This value depends on the DB instance class (for pricing information, see the Amazon RDS product page). You can increase the amount of free storage space for an instance by choosing a larger DB instance class for your instance.

InsertLatency

The amount of latency for insert queries, in milliseconds.

InsertThroughput

The average number of insert queries per second.

LoginFailures

The average number of failed login attempts per second.

MaximumUsedTransactionIDs

The age of the oldest unvacuumed transaction ID, in transactions. If this value reaches 2,146,483,648 (2^31 - 1,000,000), the database is forced into read-only mode, to avoid transaction ID wraparound. For more information, see Preventing Transaction ID Wraparound Failures in the PostgreSQL documentation.

NetworkReceiveThroughput

The amount of network throughput received from clients by each instance in the Aurora MySQL DB cluster, in bytes per second. This throughput doesn't include network traffic between instances in the Aurora DB cluster and the cluster volume.

NetworkThroughput

The amount of network throughput both received from and transmitted to clients by each instance in the Aurora MySQL DB cluster, in bytes per second. This throughput doesn't include network traffic between instances in the DB cluster and the cluster volume.

NetworkTransmitThroughput

The amount of network throughput sent to clients by each instance in the Aurora DB cluster, in bytes per second. This throughput doesn't include network traffic between instances in the DB cluster and the cluster volume.

Queries

The average number of queries executed per second.

ReadIOPS

The average number of disk I/O operations per second.

Aurora with PostgreSQL compatibility reports read and write IOPS separately, on 1-minute intervals.

ReadLatency

The average amount of time taken per disk I/O operation.

ReadThroughput

The average number of bytes read from disk per second.

ResultSetCacheHitRatio

The percentage of requests that are served by the Resultset cache.

SelectLatency

The amount of latency for select queries, in milliseconds.

SelectThroughput

The average number of select queries per second.

SwapUsage

The amount of swap space used on the Aurora PostgreSQL DB instance.

TransactionLogsDiskUsage

The amount of disk space occupied by transaction logs on the Aurora PostgreSQL DB instance.

UpdateLatency

The amount of latency for update queries, in milliseconds.

UpdateThroughput

The average number of update queries per second.

VolumeBytesUsed

The amount of storage used by your Aurora DB instance, in bytes.

This value affects the cost of the Aurora DB cluster (for pricing information, see the Amazon RDS product page).

VolumeReadIOPs

The average number of billed read I/O operations from a cluster volume, reported at 5-minute intervals.

Billed read operations are calculated at the cluster volume level, aggregated from all instances in the Aurora DB cluster, and then reported at 5-minute intervals. The value is calculated by taking the value of the Read operations metric over a 5-minute period. You can determine the amount of billed read operations per second by taking the value of the Billed read operations metric and dividing by 300 seconds. For example, if the Billed read operations returns 13,686, then the billed read operations per second is 45 (13,686 / 300 = 45.62).

You accrue billed read operations for queries that request database pages that aren't in the buffer cache and therefore must be loaded from storage. You might see spikes in billed read operations as query results are read from storage and then loaded into the buffer cache.

VolumeWriteIOPs

The average number of write disk I/O operations to the cluster volume, reported at 5-minute intervals.

WriteIOPS

The average number of disk I/O operations per second.

Aurora PostgreSQL reports read and write IOPS separately, on 1-minute intervals.

WriteLatency

The average amount of time taken per disk I/O operation.

WriteThroughput

The average number of bytes written to disk per second.

Dimensions for RDS Metrics

Amazon RDS data can be filtered along any of the following dimensions in the table below.

Dimension Description
DBInstanceIdentifier

This dimension filters the data you request for a specific database instance.

DBClusterIdentifier

This dimension filters the data you request for a specific Amazon Aurora DB cluster.

DBClusterIdentifier, Role

This dimension filters the data you request for a specific Amazon Aurora DB cluster, aggregating the metric by instance role (WRITER/READER). For example, you can aggregate metrics for all READER instances that belong to a cluster.

DatabaseClass

This dimension filters the data you request for all instances in a database class. For example, you can aggregate metrics for all instances that belong to the database class db.m1.small

EngineName

This dimension filters the data you request for the identified engine name only. For example, you can aggregate metrics for all instances that have the engine name mysql.