2006/4/3, Tom Lane <tgl@sss.pgh.pa.us>:
> "Jonah H. Harris" <jonah.harris@gmail.com> writes:
> > we're working on a prototype to reduce WAL I/O and index updates in a
> > large percentage of OLTP situations by employing an update-in-place
> > under *safe* conditions.
>
> AFAICS there are no circumstances, ever, in which update-in-place is
> "safe". (No transaction can guarantee that it will commit.)
Updates to row values that did not "escape" the currect transaction
yet (ie, rows that were created by or have their last value written by
the current transaction).
Nicolas
--
Nicolas Barbier
http://www.gnu.org/philosophy/no-word-attachments.html