On 18 Apr 2009, at 22:22, Tom Lane wrote:
>
> This is mentioned in the release notes, but I suppose we'd better
> promote it to the "observe the following incompatibilities" list...
>
This is a really funny one, because people naturally expect UNION
[ALL] to stay in the same order. Unlike the table, order here cannot
change by inserts/updates, etc.
I am sure many, even well experienced will stumble upon that one.
Me is guessing, that UNION [ALL] performance just had to be improved
for CTEs ? Or was it something completely separate.
