Re: Brain dump: btree collapsing

Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > It would be nice if VACUUM FULL would be able to compress the actual
> > index file and return unused space to the operating system. REINDEX
> > does this, but I was thinking of something a little lighter that could
> > be done automatically as part of VACUUM FULL.
>
> But indexes tend to be very dependent on physical layout. You can't
> just shove stuff around without thinking about the consequences.
> Tables (heaps) are *much* more forgiving about that.
>
> My feeling is that what we need to fix now is index bloat during normal
> operation. If you want the indexes to actually *shrink*, that's a job
> for REINDEX. Perhaps someday we can improve on that --- but let's not
> blur our focus on the immediate problem.

My point is only that while we need VACUUM and VACUUM FULL to match all
heap needs, we need a VACUUM FULL capability for indexes too. REINDEX
may be that capability, but it would be nice if we could compress out
some index space during VACUUM FULL.

--
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