Re: Add parallelism and glibc dependent only options to reindexdb

On Tue, Jul 2, 2019 at 10:28 AM Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:
>
> I wonder why this is necessary:
>
> pg_log_error("cannot reindex glibc dependent objects and a subset of objects");
>
> What's the reasoning behind that? It seems like a valid use case to me -
> imagine you have a bug database, but only a couple of tables are used by
> the application regularly (the rest may be archive tables, for example).
> Why not to allow rebuilding glibc-dependent indexes on the used tables, so
> that the database can be opened for users sooner.

It just seemed wrong to me to allow a partial processing for something
that's aimed to prevent corruption.  I'd think that if users are
knowledgeable enough to only reindex a subset of indexes/tables in
such cases, they can also discard indexes that don't get affected by a
collation lib upgrade.  I'm not strongly opposed to supporting if
though, as there indeed can be valid use cases.

> BTW now that we allow rebuilding only some of the indexes, it'd be great
> to have a dry-run mode, were we just print which indexes will be rebuilt
> without actually rebuilding them.

+1.  If we end up doing the filter in the backend, we'd have to add
such option in the REINDEX command, and actually issue all the orders
to retrieve the list.