Postgres used PostQUEL. SQL was added to Postgres by one of Stonebreaker's graduate students (Andrew Yu) around '95. By '95 Stonebreaker's lab was already working on a new distributed Postgres called Mariposa.

I don't see the contradiction you mention. Stonebraker returned to Berkeley in 1985. The article doesn't say the Postgres project started in 1985. It says Stonebraker started a post-Ingres project then. The query language at that time might have been either QUEL or POSTQUEL [1]

But the ending as it is written seems correct to me.

[1] https://dsf.berkeley.edu/papers/ERL-M85-95.pdf

I didn't say that there was a contradiction. The paper is about QUEL vs. SQL. Given that Postgres/PostgreSQL is introduced, I would think that the initial use of QUEL (PostQUEL), and how and when and why it transitioned to SQL would be highly relevant. But the end of the paper is needlessly fuzzy on this topic.

This is the ending. Quote:

"The world has since standardised on SQL, and the dreams of an alternate history exists only in the heads of those who had a hand in the early database wars. It was simply a quirk of history that System R was built within IBM, the single most powerful company in the computer industry at the time; it was a quirk that the engineers who built System R came up with a fiddly language interface as an afterthought, and it was a quirk that IBM then took that language and pushed it to become a standard … one that has lasted till today.

Of course, there was a silver lining to the whole saga. Stonebraker had forked the Ingres codebase in 1982 to create his company. Defeated by the bruising database wars of the 80s, he returned to Berkeley in 1985, and started a post-Ingres database project. Naturally, he named that database post-gres — as in, after Ingres.

And thus PostgreSQL was born."

I was trying to figure what you meant. I think I have an inkling now -- let me know if this is correct. Your quibble is with the fact the implication here is that since SQL won, Stonebraker jumped on the SQL bandwagon and created a SQL database, when in fact, he didn't -- he merely created Postgres, which ran on QUEL and didn't have SQL until much later.

I think the author made a stylistic choice to omit that detail to drive home a point, but even so nothing was said that was non-factual.

The omission, combined with the context, leads the reader to make an incorrect conclusion.

    ... he returned to Berkeley in 1985, and started a post-
    Ingres database project.

That would be Postgres.

    Naturally, he named that database post-gres — as in, after Ingres.

He says it's Postgres.

    And thus PostgreSQL was born. 

"thus" implies that the preceding discussion, about Postgres, describes the birth of PostgreSQL. Which it doesn't. At best, this is confusing, suggesting that Postgres = PostgreSQL. Postgres became PostgreSQL ten years later, once SQL was added, replacing PostQUEL. The elided details allow for different interpretations, including the wrong one, that SQL was there from the beginning. Also, the tone of the text you quoted suggests that Stonebraker learned his lesson, and just went to SQL for the Postgres project, which he definitely did not do.

I see what you're saying about that implication. I think the effects were indirect; SQL winning meant that Postgres, even though it started out supporting only POSTQUEL, had to evolve to eventually supporting SQL -- though you are correct that the cause-effect was not as direct and as inexorable as might have been implied in the prose.

I personally think eliding details was artistic license to make the prose flow better without bringing in ancillary details, but that's just me.

Stonebraker did eventually change his mind about SQL however -- if you've watched any of his recent talks he's of the opinion that most query languages will eventually and inexorably converge to some variant of SQL. (he was wrong about Mongo inventing a SQL-like query language, but that's what his philosophical commitments look like these days)