Amazon Quantum Ledger Database (Amazon QLDB)
Developer Guide

Amazon QLDB Metrics and Dimensions

When you interact with Amazon QLDB, it sends the following metrics and dimensions to CloudWatch. Storage metrics are reported every 15 minutes, and all other metrics are aggregated and reported every minute. You can use the following procedures to view the metrics for QLDB.

To view metrics using the CloudWatch console

Metrics are grouped first by the service namespace, and then by the various dimension combinations within each namespace.

  1. Open the CloudWatch console at https://console.aws.amazon.com/cloudwatch/.

  2. If necessary, change the Region. On the navigation bar, choose the Region where your AWS resources reside. For more information, see Regions and Endpoints.

  3. In the navigation pane, choose Metrics.

  4. Under the All metrics tab, choose QLDB.

To view metrics using the AWS CLI

  • At a command prompt, use the following command.

    aws cloudwatch list-metrics --namespace "AWS/QLDB"

CloudWatch displays the following metrics for QLDB.

Amazon QLDB Dimensions and Metrics

The metrics and dimensions that Amazon QLDB sends to Amazon CloudWatch are listed here.

QLDB Metrics

Metric Description
JournalStorage

The total amount of disk space used by the ledger's journal, reported in 15-minute intervals. The journal contains the complete, immutable, and verifiable history of all the changes to your data.

Units: Bytes

Dimensions: LedgerName

IndexedStorage

The total amount of disk space used by the ledger's tables, indexes, and indexed history, reported in 15-minute intervals. Indexed storage consists of ledger data that is optimized for high-performance queries.

Units: Bytes

Dimensions: LedgerName

ReadIOs

The number of disk read I/O operations, reported in one-minute intervals.

Units: Count

Dimensions: LedgerName

WriteIOs

The number of disk write I/O operations, reported in one-minute intervals.

Units: Count

Dimensions: LedgerName

CommandLatency

The amount of time taken for data operations, reported in one-minute intervals.

Units: Milliseconds

Dimensions: LedgerName, CommandType

OccConflictExceptions

The number of requests to QLDB that generate an OccConflictException. For information about optimistic concurrency control (OCC), see Amazon QLDB Concurrency Model.

Units: Count

Session4xxExceptions

The number of requests to QLDB that generate an HTTP 4xx error.

Units: Count

Session5xxExceptions

The number of requests to QLDB that generate an HTTP 5xx error.

Units: Count

SessionRateExceededExceptions

The number of requests to QLDB that generate a SessionRateExceededException.

Units: Count

Dimensions for QLDB Metrics

The metrics for QLDB are qualified by the values for the account, ledger name, or command type. You can use the CloudWatch console to retrieve QLDB data along any of the dimensions in the following table.

Dimension Description
LedgerName

This dimension limits the data to a specific ledger. This value can be any ledger name in the current AWS Region and the current AWS account.

CommandType

This dimension limits the data to one of the following QLDB data API commands:

  • AbortTransaction

  • CommitTransaction

  • EndSession

  • ExecuteStatement

  • FetchPage

  • StartSession

  • StartTransaction