On Wed, Jan 10, 2024 at 8:46 AM Bruce Momjian <br...@momjian.us> wrote:
> On Wed, Jan 10, 2024 at 12:29:54PM +0100, Torsten Förtsch wrote: > > > > > To me that was a bit surprising. I would have expected it to fail with > > something like "can't update the same row twice in the same command". > > > > If I check the table content after the query I see the i=i+1 part was > executed. > > > > Is this expected behavior? > > Yes, this surprised me too. It is mostly documented. https://www.postgresql.org/docs/current/queries-with.html#QUERIES-WITH-MODIFYING """ Only one of the modifications takes place, but it is not easy (and sometimes not possible) to reliably predict which one. ... In particular avoid writing WITH sub-statements that could affect the same rows changed by the main statement or a sibling sub-statement. The effects of such a statement will not be predictable. """ Yes, an error would be nice, but the effort put forth stops at unpredictable, and saying just don't do it. David J.
