On Wed, Dec 16, 2020 at 1:27 AM Michael Paquier <mich...@paquier.xyz> wrote: > > On Tue, Dec 15, 2020 at 06:34:16PM +0100, Magnus Hagander wrote: > > Is this really a common enough operation that we need it in the main > > grammar? > > > > Having the functionality, definitely, but what if it was "just" a > > function instead? So you'd do something like: > > SELECT 'reindex index ' || i FROM pg_blah(some, arguments, here) > > \gexec > > > > Or even a function that returns the REINDEX commands directly (taking > > a parameter to turn on/off concurrency for example). > > > > That also seems like it would be easier to make flexible, and just as > > easy to plug into reindexdb? > > Having control in the grammar to choose which index to reindex for a > table is very useful when it comes to parallel reindexing, because > it is no-brainer in terms of knowing which index to distribute to one > job or another. In short, with this grammar you can just issue a set > of REINDEX TABLE commands that we know will not conflict with each > other. You cannot get that level of control with REINDEX INDEX as it
(oops, seems I forgot to reply to this one, sorry!) Uh, isn't it almost exactly the opposite? If you do it in the backend grammar you *cannot* parallelize it between indexes, because you can only run one at a time. Whereas if you do it in the frontend, you can. Either with something like reindexdb that could do it automatically, or with psql as a copy/paste job? > may be possible that more or more commands conflict if they work on an > index of the same relation because it is required to take lock also on > the parent table. Of course, we could decide to implement a > redistribution logic in all frontend tools that need such things, like > reindexdb, but that's not something I think we should let the client > decide of. A backend-side filtering is IMO much simpler, less code, > and more elegant. It's simpler in the simple case, i agree with that. But ISTM it's also a lot less flexible for anything except the simplest case... -- Magnus Hagander Me: https://www.hagander.net/ Work: https://www.redpill-linpro.com/
