Re: [Proposal] Allow users to specify multiple tables in VACUUM commands

On Mon, Sep 4, 2017 at 11:47 PM, Bossart, Nathan <bossartn(at)amazon(dot)com> wrote:
> I've made this change in v14 of the main patch.
>
> In case others had opinions regarding the de-duplication patch, I've
> attached that again as well.

+ /*
+ * Create the relation list in a long-lived memory context so that it
+ * survives transaction boundaries.
+ */
+ old_cxt = MemoryContextSwitchTo(AutovacMemCxt);
+ rangevar = makeRangeVar(tab->at_nspname, tab->at_relname, -1);
+ rel = makeVacuumRelation(rangevar, NIL, tab->at_relid);
+ rel_list = list_make1(rel);
+ MemoryContextSwitchTo(old_cxt);
That's way better, thanks for the new patch.

So vacuum_multiple_tables_v14.patch is good for a committer in my
opinion. With this patch, if the same relation is specified multiple
times, then it gets vacuum'ed that many times. Using the same column
multi-times results in an error as on HEAD, but that's not a new
problem with this patch.

So I would tend to think that the same column specified multiple times
should cause an error, and that we could let VACUUM run work N times
on a relation if it is specified this much. This feels more natural,
at least to me, and it keeps the code simple.
--
Michael