On Tue, Dec 01, 2020 at 11:07:30AM -0300, Alvaro Herrera wrote:
> > Should it be done in an AtCommit hook or something like that ?
>
> I didn't like this idea much on first read, on extensibility grounds,
> but perhaps it's not so bad because we can generalize it whenever
> there's pressure to add a second type of work-item (*if* that ever
> happens).
>
> I suppose the idea is that index_drop saves the index OID when a BRIN
> index with autosummarization=on is dropped, and then the
> AtCommit_WorkItems() call scans the items list and drops those that
> match any OIDs in the list. (It does require to be mindful of subxact
> aborts, of course.)
This was an idea I made up - I don't know any of the details of this, but if
you give a hint I could look at it more. There'd (still) be a race window, but
I think that's ok.
Another idea is if perform_work_item() were responsible for discarding
relations which disappear. Currently it does this, which is racy since it
holds no lock.
cur_relname = get_rel_name(workitem->avw_relation);
cur_nspname = get_namespace_name(get_rel_namespace(workitem->avw_relation));
cur_datname = get_database_name(MyDatabaseId);
if (!cur_relname || !cur_nspname || !cur_datname)
goto deleted2;
--
Justin
