alvherre

Before version 10, the versioning scheme was different, and the first number was increased about once every five years: for example, 9.6 and 9.5 were consecutive yearly major releases. Version 7.0 was released around year 2000.

Postgres has a strict schedule of quarterly bugfix releases, and only deviates from that when serious bugs occur (very rare). So, no.

Yes, MERGE is specified by the SQL standard. Our implementation (Postgres) aims to conform to the standard, so it should roughly match what both Oracle and SQL Server offer.

(Microsoft seems to have added a BY TARGET/BY SOURCE specification to the WHEN NOT MATCHED clause, which is not in the standard. Oracle seems to do DELETE in a different, nonstandard way.)

"Upsert" (which is called INSERT ON CONFLICT UPDATE in Postgres) is a different animal. It is not part of the SQL standard, which is why every database system does its own stuff.

We strive to have exactly one feature or bugfix per commit. Squashing commits to a single one does not mean we mix stuff randomly.