AWS recently announced that new customers can no longer sign up for Amazon Quantum Ledger Database (QLDB), a managed service providing an immutable transaction log maintained by a central trusted authority. All existing databases will be shut down in one year, and current users are encouraged to migrate to Aurora PostgreSQL.
Even though no formal announcements were made, the cloud provider updated their documentation and sent an email to existing customers, highlighting that support for QLDB will end on July 31, 2025.
First announced at re:Invent 2018, QLDB was initially available in preview form and became generally available in 2019. The ledger database provides a complete and cryptographically verifiable history of all changes made to application data. At the time, Jeff Barr, vice president and chief evangelist at AWS, wrote:
These features make QLDB a great fit for banking & finance, e-commerce, transportation & logistics, HR & payroll, manufacturing, and government applications, and many other use cases that need to maintain the integrity and history of stored data.
The cloud provider recently posted an article explaining why Aurora PostgreSQL is a suitable alternative to QLDB for common ledger database use cases. Features and services such as pgAudit, Amazon S3, and Aurora Database Activity Streams are highlighted as replacements for the underlying journal, history, and QLDB streams. Dan Blaner, principal specialist solutions architect at AWS, explains the main challenge:
In Amazon QLDB, the underlying journal stores an immutable record of all committed transactions, including query statements and data definition commands. The journal’s transaction history can be exported into an Amazon Simple Storage Service (Amazon S3) bucket and accessed for auditing purposes. Amazon Aurora PostgreSQL does not keep a permanent, immutable record of changes. Instead, that history must be generated as audit data and stored outside of the database.
A separate article outlines the migration steps to Amazon Aurora PostgreSQL. The two-phase solution architecture involves a full load and ongoing replication. It includes S3, Step Functions, an AWS Glue job to extract ledger document revisions from the exported files and transform them into CSV format, and the AWS Database Migration Service.
Source: AWS blog
The lack of a formal announcement surprised many users. Corey Quinn, chief cloud economist at The Duckbill Group, comments:
Ugh. So QLDB was deprecated; it’s going away completely next year (...) Sure, they’ll announce trivial region expansions of forgettable features all day, but a full on service deprecation? (...) QLDB was a good database; its only flaw was being a blockchain-adjacent offering that didn’t let customers babble on about blockchain for half a decade.
In a popular Reddit thread, user redrabbitreader highlights a potential challenge:
The customers who are using it will risk losing their data integrity guarantees during the migration process (that whole "transparent, immutable, and cryptographically verifiable transaction log." feature set of this service). I can only imagine the headaches this will cause for some businesses.
In the past, AWS was known for never shutting down existing services. However, in the last year, several services have been deprecated or shut down, including Amazon OpsWorks, Aurora Serverless V1, and Amazon Honeycode. User FlinchMaster comments on Reddit:
Maybe this makes sense for the shareholders, but it feels like such a Day Two thing to do. The fact that AWS doesn't just shut down services is part of what made it so appealing compared to things like GCP. The story about how SimpleDB is still around has become legendary.
AWS encourages customers to contact their AWS representatives to plan their migrations.