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Robert Haas Attributes PostgreSQL 19's Late Release and Feature Reverts to LLM-Found Bugs, Citing a Jump of More Than 60% in Back-Patched Commits

In a post LWN linked on October 30, PostgreSQL developer Robert Haas says LLM-found bug reports drove more back-patching and late reverts; the project's own announcements give no cause.

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Overview

Robert Haas, a PostgreSQL developer, has published a post titled “Postgres 19 is late, and it’s AI’s fault,” in which he argues that bug reports found with large language models (LLMs) explain why PostgreSQL 19 is arriving later than recent major releases. LWN.net linked to the post on October 30, 2026. The explanation is Haas’s own account; the project’s release announcements, discussed below, state no cause for the schedule change.

What the Post Says

Haas writes that major releases have become predictable over the past decade, arriving “no earlier than the middle of September, and no later than the middle of October.” He adds that this year PostgreSQL 19 “most likely won’t be released until November, and it’s not impossible that the project could decide to postpone the release further.”

He also points to late feature reverts. According to the post, “UPDATE/DELETE FOR PORTION OF, SQL Property Graph Queries (SQL/PGQ), and ALTER TABLE … MERGE PARTITION/SPLIT PARTITION were all reverted between August 27 and September 15.” His answer to what happened is, in his words, “The short answer is that LLMs happened.”

The commit counts

Haas supports the argument with commit counts for the period from April 8 to September 25. According to the post:

  • In 2025 there were 1037 commits to the master branch and 724 commits to REL_18_STABLE. In 2026 the same period saw 1443 commits to the master branch and 1169 commits to REL_19_STABLE.
  • Commits to master alone, between feature freeze and September 25, “actually declined slightly from last year to this year,” while the number of back-patched commits “jumped by more than 60%.”
  • Commits back-patched to at least one prior release rose by more than 74% in a single year, from 248 commits to REL_17_STABLE in 2025 to 433 commits to REL_18_STABLE in 2026.

Haas considers and sets aside one alternative reading: “It’s possible that some of this jump is the result of committers making more mistakes this year than they did last year, but I don’t think anyone who works on the project really believes that’s the main cause.” He attributes the rise to “a huge number of people on the Internet” reporting bugs they found using LLMs.

Why that would delay a release

The post names two factors. First, because more bugs are being found, fixing them takes longer; he writes that “LLMs can draft fixes, but those fixes aren’t always correct or compliant with PostgreSQL standards,” so humans still need to review and commit them. Second, “time that would have been spent reviewing what went into the release got diverted into addressing security issues and other bugs in the back-branches,” which made it slower to decide what to revert.

Haas does not describe the delay as a serious problem: “I don’t think that the delay in shipping PostgreSQL 19 is particularly concerning.” He calls the long-term picture “less clear and in some ways more troubling” and asks how the project will catch up and continue to innovate, answering: “Right now, I’m not sure.” He also writes that “Every feature that we write from now until the end of our careers will be scrutinized by AI.”

What the Project Has Announced

The PostgreSQL Global Development Group’s Beta 4 announcement, posted September 24, said the release candidate “should occur in early October” and that general availability “may also occur in October.” It listed reverts of SQL/PGQ support, online enabling and disabling of data checksums, the FOR PORTION OF temporal updates and deletes, and ALTER TABLE ... MERGE PARTITIONS and ALTER TABLE ... SPLIT PARTITIONS. It said the community “strongly believes that, first and foremost, PostgreSQL must be reliable,” but did not give a cause for the reverts.

The RC 1 announcement, posted October 15, sets general availability for November 19, 2026. It plans RC 2 for November 12, the date of the next scheduled update release, which it says “will include a large number of fixes.” The release team decided to include those fixes in PostgreSQL 19 before general availability. The announcement does not mention LLMs or the source of the bug reports. The Herald covered both releases earlier, including the Beta 4 reverts and the RC 1 schedule.

What We Don’t Know

  • Whether other PostgreSQL committers or the release team share Haas’s account. The post is one developer’s explanation, and the project announcements are silent on cause.
  • How many of the back-patched commits correspond to LLM-assisted bug reports. Haas’s figures are commit counts, and his link between them and LLM use is an inference he states rather than a measured breakdown in the post.
  • Whether general availability will hold at November 19. The RC 1 announcement says it should, “[u]nless an issue is discovered that requires a delay or an additional release candidate,” while Haas writes that a further postponement is “not impossible.”