Re: Block level parallel vacuum WIP

Robert Haas wrote:
> On Tue, Aug 23, 2016 at 11:17 AM, Alvaro Herrera
> <alvherre@2ndquadrant.com> wrote:
> > Robert Haas wrote:
> >> 2. When you finish the heap scan, or when the array of dead tuple IDs
> >> is full (or very nearly full?), perform a cycle of index vacuuming.
> >> For now, have each worker process a separate index; extra workers just
> >> wait.  Perhaps use the condition variable patch that I posted
> >> previously to make the workers wait.  Then resume the parallel heap
> >> scan, if not yet done.
> >
> > At least btrees should easily be scannable in parallel, given that we
> > process them in physical order rather than logically walk the tree.  So
> > if there are more workers than indexes, it's possible to put more than
> > one worker on the same index by carefully indicating each to stop at a
> > predetermined index page number.
> 
> Well that's fine if we figure it out, but I wouldn't try to include it
> in the first patch.  Let's make VACUUM parallel one step at a time.

Sure, just putting the idea out there.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
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