On 8 December 2017 at 11:23, Robert Haas <robertmh...@gmail.com> wrote: > On Thu, Dec 7, 2017 at 4:57 PM, David Rowley > <david.row...@2ndquadrant.com> wrote: >> That's true, but is it worth inventing/maintaining an ATTACH syntax >> for that? It's not a very common case that multiple matching indexes >> existing. If it is worth it, do we need DETACH at all? > > I think it is totally worth it. A little piece of extra DDL syntax > isn't that really costing us anything. Your proposed approach > probably still has obscure failure cases - e.g. I bet the > deadlock-avoidance logic in parallel restore won't know about the > dependency on a seemingly-unrelated object. Also, the use of a > seemingly-useless REPLACE syntax in every dump file will probably > confuse at least a few users, and maybe a few developers, too. I > think there is considerable value, both for the system and for the > humans who use it, in having something that has *exactly* the > semantics we want rather than *almost* the semantics we want. > > I suppose if we want to get cute, we could have ONLY the ATTACH > syntax; if you attach an index for a partition that already has an > index attached, that could mean attach to the new one instead of the > old one (i.e. replace). But I would just add support for both ATTACH > and REPLACE and call it good.
ATTACH/REPLACE sounds fine. My objection was more about the DETACH/ATTACH method to replace an index. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
