Amazon Quantum Ledger Database (QLDB)

  • Fully managed ledger database that provides a transparent, immutable, and cryptographically verifiable transaction log ‎owned by a central trusted authority.
  • Used to track all application data changes, and maintain a complete and verifiable history of changes over time
  • Amazon QLDB is serverless.  No capacity provisioning required or setting read/write limits.
  • QLDB transactions are ACID (atomicity, consistency, isolation, and durability) compliant.
  • Amazon QLDB uses PartiQL as its query language.

How it Works

amazon qldb

Common Use Cases:

  • Finance
    • Banks can use Amazon QLDB to easily store an accurate and complete record of all financial transactions, instead of building a custom ledger with complex auditing functionality.
  • Insurance
    • Insurance companies can use Amazon QLDB to track the entire history of claim transactions. Whenever a conflict arises, Amazon QLDB can cryptographically verify the integrity of the claims data.

Components Of QLDB

IT Certification Category (English)728x90
  • Ledger
    • Consists of tables and journals that keep all of the immutable histories of changes in the table.
  • Tables 
    • Contains a collection of document revisions.
  • Journal
    • An immutable transactions log where transactions are appended as a sequence of blocks that are cryptographically chained together to provide a secure verification and immutability of the history of changes to your ledger data.
    • Only the data’s history of change cannot be altered and not the data itself.
  • Current State
    • The current state is similar to a traditional database where you can view and query the latest data.
  • History
    • The history is a table where you can view and query the history of all the data and every change ever made to the data.


  • Amazon QLDB can execute 2 – 3X as many transactions than ledgers in common blockchain frameworks.


  • Amazon QLDB automatically scales based on the workloads of your application.


  • Multiple copies of QLDB ledger are replicated across availability zones in a region. You can still continue to operate QLDB even in the case of zone failure.
  • Ensures redundancy within a region.
  • Also ensures full recovery when an availability zone goes down.

Backup and Restore

  • You can export the contents of your QLDB journals to S3 as a backup plan.


  • Amazon QLDB uses SHA-256 hash function to make a secure file representation of your data’s change history called digest. The digest serves as a proof of your data’s change history, enabling you to go back at a point in time to verify the validity and integrity of your data changes.
  • All data in transit and at rest are encrypted by default.
  • Uses AWS-owned keys for encryption of data.
  • The authentication is done by attaching a signature to the HTTP requests. The signature is then verified using the AWS credentials.
  • Integrated with AWS Private Link.


  • You are billed based on five categories
    • Write I/Os
      • Pricing per 1 million requests
    • Read I/Os
      • Pricing per 1 million requests
    • Journal Storage Rate
      • Pricing per GB-month
    • Indexed Storage Rate
      • Pricing per GB-month
    • Data Transfer OUT From Amazon QLDB To Internet
      • You are charged based on the amount of data transferred per month. The rate varies for different regions.


  • Amazon QLDB does not support Backup and Restore. But you can export your data from QLDB to S3.
  • Does not support Point-in-time restore feature.
  • Does  not support cross-region replication.
  • Does not support the use of customer managed CMKs (Customer Managed Keys).

Note: If you are studying for the AWS Certified Database Specialty exam, we highly recommend that you take our AWS Certified Database – Specialty Practice Exams and read our Database Specialty exam study guide.

AWS Certified Database Specialty Practice Exams


Pass your AWS Certifications on your First Try with the Tutorials Dojo Portal

Tutorials Dojo portal

Our Bestselling AWS Certified Solutions Architect Associate Practice Exams

AWS Certified Solutions Architect Associate Practice Exams

Enroll Now – Our AWS Practice Exams with 95% Passing Rate

AWS Practice Exams Tutorials Dojo

Tutorials Dojo Study Guide and Cheat Sheets eBooks

Tutorials Dojo Study Guide and Cheat Sheets-2

FREE Intro to Cloud Computing for Beginners

FREE AWS Practice Test Samplers

Browse Other Courses

Generic Category (English)300x250

Recent Posts