Robert Haas <robertmh...@gmail.com> writes: > I vote for rejecting both of these patches.
I see what James is on about here, but I agree that these specific changes don't help much. What would actually be desirable IMO is a separate section somewhere explaining the performance characteristics of ALTER TABLE. (We've also kicked around the idea of EXPLAIN for ALTER TABLE, but that's a lot more work.) This could coalesce the parenthetical remarks that exist in ddl.sgml as well as alter_table.sgml into something a bit more unified and perhaps easier to follow. In particular, it should start by defining what we mean by "table rewrite" and "table scan". I don't recall at the moment whether we define those in multiple places or not at all, but as things stand any such discussion would be pretty fragmented. regards, tom lane