On Wed, Aug 27, 2014 at 7:43 PM, Peter Geoghegan <pg@heroku.com> wrote:
> There are some restrictions on what this auxiliary update may do, but
> FWIW there are considerably fewer than those that the equivalent MySQL
> or SQLite feature imposes on their users.
I realized that I missed a few cases here. For one thing, the posted
patch fails to arrange for the UPDATE post-parse-analysis tree
representation to go through the rewriter stage (on the theory that
user-defined rules shouldn't be able to separately affect the
auxiliary UPDATE query tree), but rewriting is at least necessary so
that rewriteTargetListIU() can expand a "SET val = DEFAULT"
targetlist, as well as normalize the ordering of the UPDATE's tlist.
Separately, the patch fails to defend against certain queries that
ought to be disallowed, where a subselect is specified with a subquery
expression in the auxiliary UPDATE's WHERE clause.
These are garden-variety bugs that aren't likely to affect the kind of
high-level design discussion that I'm looking for here. I'll post a
fixed version in a few days time.
--
Peter Geoghegan
