Bruce Momjian: Postgres Blog

Postgres 19 Release Notes

Wed, 15 Apr 2026 17:15:01 -0400

I have just completed the first draft of the Postgres 19 release notes. It includes little developer community feedback and still needs more XML markup and links. This year I have created a wiki page explaining the process I use.

The release note feature count is 212, which includes a strong list of administrative and monitoring features. Postgres 19 Beta 1 should be released in a few months. The final release is planned for September/October of this year.

COMMENT to the MCP Rescue

Mon, 16 Mar 2026 12:00:00 -0400

The COMMENT command has been in Postgres for decades. It allows text descriptions to be attached to almost any database object. During its long history, it was mostly seen as a nice-to-have addition to database schemas, allowing administrators and developers to more easily understand the schema. Tools like pgAdmin allow you to assign and view comments on database objects.

Now, in the AI era, there is something else that needs to understand database schemas — MCP clients. Without database object comments, MCP clients can only use the database schemas, object names, and constraints. With database comments, database users can supply valuable information to allow MCP clients to more effectively match schema objects to user requests and potentially generate better SQL queries. If database users don't want to add such comments, it might be possible for generative AI to create appropriate comments, perhaps by analyzing data in the tables.

The MySQL Shadow

Wed, 11 Mar 2026 12:00:00 -0400

For much of Postgres's history, it has lived in the shadow of other relational systems, and for a time even in the shadow of NoSQL systems. Those shadows have faded, but it is helpful to reflect on this outcome.

On the proprietary side, most database products are now in maintenance mode. The only database to be consistently compared to Postgres was Oracle. Long-term, Oracle was never going to be able to compete against an open source development team, just like Sun's Solaris wasn't able to compete against open source Linux. Few people would choose Oracle's database today, so it is effectively in legacy mode. The Oracle shadow is clearly fading. In fact, almost all enterprise infrastructure software is open source today.

The MySQL shadow is more complex. MySQL is not proprietary, since it is distributed as open source, so it had the potential to ride the open source wave into the enterprise, and it clearly did from the mid-1990s to the mid-2000s. However, something changed, and MySQL has been in steady decline for decades. Looking back, people want to ascribe a reason for the decline:

Sun buying MySQL AB
Oracle buying Sun
Poor stewardship of MySQL by Oracle, including recent layoffs

New Presentation

Sat, 07 Mar 2026 12:00:00 -0400

I just gave a new presentation at SCALE titled The Wonderful World of WAL. I am excited to have this second new talk this year. (I have one more queued up.)

I have always wanted to do a presentation about the write-ahead log (WAL) but I was worried there was not enough content for a full talk. As more features were added to Postgres that relied on the WAL, the talk became more feasible, and at 103 slides, maybe I waited too long.

I had a full hour to give the talk at SCALE, and that was helpful. I was able to answer many questions during the talk, and that was important — many of the later features rely on earlier ones, e.g., point-in-time recovery (PITR) relies heavily on crash recovery, and if you don't understand how crash recovery works, you can't understand PITR. By taking questions at the end of each section, I could be sure everyone understood. The questions showed that the audience of 46 understood the concepts because they were asking about the same issues we dealt with in designing the features:

How does server start know if crash recovery is needed?
Can dirty shared buffers be written to storage before the WAL for the transaction that dirtied them is written?
Can the WAL and heap/index storage get out of sync?
How is the needed WAL accurately retained for replica servers?
Can logical replicas be used as failover servers?

New Presentation

Wed, 28 Jan 2026 12:00:00 -0400

I just gave a new presentation at Prague PostgreSQL Developer Day titled What's Missing in Postgres? It's an unusual talk because it explains the missing features of Postgres, and why. One thing I learned in writing the talk is that the majority of our missing features are performance-related, rather than functionality-related. I took many questions:

some pointed out that extensions supply much of this missing functionality
some supported the lack of features because the features are either unnecessary or harmful
some features are in-progress (slide 31)

Thanks to Melanie Plageman for the idea of this talk.