Matt Roberts <matt@runtime-collective.com> writes:
> Please accept my apologies if this is answered elsewhere in the archives
> or docs but I have searched without luck.
>
> I've always assumed that default ordering of selects are based on a first
> in first out principle and that this remains true at the row level despite
> edits to columns.
There is no guaranteed ordering of rows without an ORDER BY clause.
VACUUM will change the row ordering as it moves tuples around to free
up space. If you want a guaranteed order, use a key field and ORDER BY.
-Doug
--
Let us cross over the river, and rest under the shade of the trees.
--T. J. Jackson, 1863