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I'm scratching my head trying to think why AWS would have worked on this? I can't think of it being used in any of their products. RDS uses block replication.

I'm scratching my head trying to think why AWS would have worked on this? I can't think of it being used in any of their products. RDS uses block replication. Aurora uses it's own SAN replication layer. DMS maybe?

gotimo 1y ago
probably [Aurora DSQL](https://aws.amazon.com/rds/aurora/dsql/ https://aws.amazon.com/rds/aurora/dsql/) which released a couple of weeks ago
- fizx 1y ago
  I thought dsql was distributed transactions. :thinking:
  - mjb 1y ago
    DSQL does use distributed transactions to offer active-active alongside strong consistency and isolation guarantees. Here's how: https://brooker.co.za/blog/2024/12/05/inside-dsql-writes.html https://brooker.co.za/blog/2024/12/05/inside-dsql-writes.htm...
- loginatnine 1y ago
  It's definitely DSQL with the multi-region active active feature[1]. [1]https://aws.amazon.com/rds/aurora/dsql/features/#topic-1 https://aws.amazon.com/rds/aurora/dsql/features/#topic-1
  - riknos314 1y ago
    DSQL only uses Postgres for the query processor layer, so it doesn't require a replication library within postgres itself. Definitely NOT from DSQL. > We’re not using any of the storage or transaction processing parts of PostgreSQL, but are using the SQL engine, an adapted version of the planner and optimizer, and the client protocol implementation. [1] Rather, DSQL seems to do its region replication using the distributed journal abstraction [2]. [1] https://brooker.co.za/blog/2024/12/04/inside-dsql.html https://brooker.co.za/blog/2024/12/04/inside-dsql.html [2] https://brooker.co.za/blog/2024/12/06/inside-dsql-cap.html https://brooker.co.za/blog/2024/12/06/inside-dsql-cap.html
- tneely 1y ago
  DSQL uses an internal service, Journal[1], for its mutli-region writes. [1]: https://www.allthingsdistributed.com/2025/05/just-make-it-scale-an-aurora-dsql-story.html https://www.allthingsdistributed.com/2025/05/just-make-it-sc...
deleted 1y ago
[deleted]
the_precipitate 1y ago
Yeah, and this doesn't seems to be that useful. At least I don't understand why one should do this on a strong ACID relational database.
- hobs 1y ago
  In my experience multi-writer is because of latency or HADR stuff - have all your data in all regions at the same time, but the method (via the tlog) seems like it sort of defeats what those sorts of systems might be able to historically do (write multiple places from the app at the same time so as to have the lowest possible chance of data loss.)
  - shermantanktop 1y ago
    Yes, I call it spoke-and-hub. The sharded spokes accept the writes and replicate back to the hub, where all shards coexist. Useful for metric ingestion. Not useful for bank ledgers or whatever.
    - hobs 1y ago
      Yeah, some instances also have all the shards maintain all the state and just accept writes in your partition of values, merge replication in sql server works like this.
ForHackernews 1y ago
Apparently they've offered it as a feature in RDS Postgres for a couple years now https://aws.amazon.com/about-aws/whats-new/2023/10/pgactive-active-active-replication-extension-postgre-sql-amazon-rds/ https://aws.amazon.com/about-aws/whats-new/2023/10/pgactive-... But only last month did they officially release it as open source to the community https://aws-news.com/article/2025-06-09-announcing-open-sourcing-pgactive-active-active-replication-extension-for-postgresql https://aws-news.com/article/2025-06-09-announcing-open-sour...
- everfrustrated 1y ago
  Thanks, that seems to match.
- 0xFF0123 1y ago
  A lot of theorising above, but this seems like the earliest reference
thayne 1y ago
> Aurora uses it's own SAN replication layer I don't think that is used for cross region replication
cfycom 1y ago
From the readme of the repo: "Use cases for this include running a Multi-Region high availability database cluster"
prdpx7 1y ago
i think AWS is using pgactive to sell "Aurora Postgres Global" https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/aurora-global-database.html https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide...

gotimo 1y ago

probably [Aurora DSQL](https://aws.amazon.com/rds/aurora/dsql/ https://aws.amazon.com/rds/aurora/dsql/) which released a couple of weeks ago

fizx 1y ago
I thought dsql was distributed transactions. :thinking:
- mjb 1y ago
  DSQL does use distributed transactions to offer active-active alongside strong consistency and isolation guarantees. Here's how: https://brooker.co.za/blog/2024/12/05/inside-dsql-writes.html https://brooker.co.za/blog/2024/12/05/inside-dsql-writes.htm...
loginatnine 1y ago
It's definitely DSQL with the multi-region active active feature[1]. [1]https://aws.amazon.com/rds/aurora/dsql/features/#topic-1 https://aws.amazon.com/rds/aurora/dsql/features/#topic-1
- riknos314 1y ago
  DSQL only uses Postgres for the query processor layer, so it doesn't require a replication library within postgres itself. Definitely NOT from DSQL. > We’re not using any of the storage or transaction processing parts of PostgreSQL, but are using the SQL engine, an adapted version of the planner and optimizer, and the client protocol implementation. [1] Rather, DSQL seems to do its region replication using the distributed journal abstraction [2]. [1] https://brooker.co.za/blog/2024/12/04/inside-dsql.html https://brooker.co.za/blog/2024/12/04/inside-dsql.html [2] https://brooker.co.za/blog/2024/12/06/inside-dsql-cap.html https://brooker.co.za/blog/2024/12/06/inside-dsql-cap.html
tneely 1y ago
DSQL uses an internal service, Journal[1], for its mutli-region writes. [1]: https://www.allthingsdistributed.com/2025/05/just-make-it-scale-an-aurora-dsql-story.html https://www.allthingsdistributed.com/2025/05/just-make-it-sc...

deleted 1y ago

[deleted]

the_precipitate 1y ago

Yeah, and this doesn't seems to be that useful. At least I don't understand why one should do this on a strong ACID relational database.

hobs 1y ago
In my experience multi-writer is because of latency or HADR stuff - have all your data in all regions at the same time, but the method (via the tlog) seems like it sort of defeats what those sorts of systems might be able to historically do (write multiple places from the app at the same time so as to have the lowest possible chance of data loss.)
- shermantanktop 1y ago
  Yes, I call it spoke-and-hub. The sharded spokes accept the writes and replicate back to the hub, where all shards coexist. Useful for metric ingestion. Not useful for bank ledgers or whatever.
  - hobs 1y ago
    Yeah, some instances also have all the shards maintain all the state and just accept writes in your partition of values, merge replication in sql server works like this.

ForHackernews 1y ago

Apparently they've offered it as a feature in RDS Postgres for a couple years now https://aws.amazon.com/about-aws/whats-new/2023/10/pgactive-active-active-replication-extension-postgre-sql-amazon-rds/ https://aws.amazon.com/about-aws/whats-new/2023/10/pgactive-... But only last month did they officially release it as open source to the community https://aws-news.com/article/2025-06-09-announcing-open-sourcing-pgactive-active-active-replication-extension-for-postgresql https://aws-news.com/article/2025-06-09-announcing-open-sour...

everfrustrated 1y ago
Thanks, that seems to match.
0xFF0123 1y ago
A lot of theorising above, but this seems like the earliest reference

thayne 1y ago

> Aurora uses it's own SAN replication layer I don't think that is used for cross region replication

cfycom 1y ago

From the readme of the repo: "Use cases for this include running a Multi-Region high availability database cluster"

prdpx7 1y ago

i think AWS is using pgactive to sell "Aurora Postgres Global" https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/aurora-global-database.html https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide...