Re: Automatic free space map filling

Zeugswetter Andreas DCP SD wrote:
>
> > > But what about index clearing? When do you scan each index?
> >
> > At the end of each iteration (or earlier, depending on
> > maintenance_work_mem). So for each iteration you would need
> > to scan the indexes.
> >
> > Maybe we could make maintenance_work_mem be the deciding
> > factor; after scanning the indexes, do the release/reacquire
> > locks cycle.
>
> But you could do the indexes first and remember how far you can
> vacuum the heap later.
>
> So you might as well do each index separately first and remember
> how far you can go with the heap for each one.
> Then do the heap with a special restriction that comes from what you
> remembered from the indexes.
> You can now separate the heap vacuum in arbitrarily large transactions,
> since the indexes are already taken care of.
>
> (You only vacuum to the point of the eldest vacuumed index)

I thought you need to know the heap tids to remove from the index, so
how do you do the index first?

--
Bruce Momjian http://candle.pha.pa.us
SRA OSS, Inc. http://www.sraoss.com

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