On Sat, Jul 19, 2014 at 09:55:19PM -0700, Peter Geoghegan wrote: > At a high level SQL MERGE is quite distinct from UPSERT, in that it is > a utility command that performs inserts, updates and deletes while > avoiding race conditions (e.g. unique constraint violations) on a more > or less best effort basis. MERGE is conceptually messy. In contrast > UPSERT is actually atomic, and having its behavior be relatively easy > to reason about ought to be the top priority. There is a *really* big > demand for UPSERT from users, not MERGE, although MERGE is certainly > useful too.
FWIW, I agree. MERGE is hard enough as it is, but trying to guarentee some kind of atomicity makes it nigh on impossible. Indeed, after reading what you wrote I think it may well be impossible to make it atomic *and* make it perform in the general case. So, +1 UPSERT. Have a nice day, -- Martijn van Oosterhout <klep...@svana.org> http://svana.org/kleptog/ > He who writes carelessly confesses thereby at the very outset that he does > not attach much importance to his own thoughts. -- Arthur Schopenhauer
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