Re: Re: [PATCH] Enforce that INSERT...RETURNING preserves the order of multi rows - Mailing list pgsql-hackers

Andrew Dunstan <andrew@dunslane.net> writes:
> Er, what?

>     with orig_inserts as
>     (
>          insert into table_1
>          ...
>          returning *
>     ),
>     ordered_inserts as
>     (
>          select * from orig_inserts
>          order by ...
>     )
>     insert into table_2
>     select * from ordered_inserts ...;

I'm not exactly following what that proves?  It seems like this is still
making a not-guaranteed assumption, which is that the outer INSERT isn't
going to choose to rearrange the order of the rows coming from the CTE.
Strictly speaking, even "SELECT * FROM ordered_inserts" isn't promising
anything about row order.
        regards, tom lane