Re: Vertical Partitioning with TOAST

Jim C. Nasby wrote:
> On Thu, Dec 08, 2005 at 12:59:47AM -0500, Tom Lane wrote:
> > "Jim C. Nasby" <jim@nasby.net> writes:
> > > This seems like a useful feature to add, allowing for easy built-in
> > > verticle partitioning. Are there issues with the patch as-is?
> > 
> > Other than the ones mentioned by the poster?
> > 
> > It seemed to me more like a not-too-successful experiment than something
> > ready for application.  If you take the viewpoint that this is just
> > another TOAST storage strategy, I think it's pretty useless.  A large
> > field value is going to get toasted anyway with the regular strategy,
> > and if your column happens to contain some values that are not large,
> > forcing them out-of-line anyway is simply silly.  (You could make a case
> > for making the threshold size user-controllable, but I don't see the
> > case for setting the threshold to zero, which is what this amounts to.)
> 
> Valid point. I do think there's a lot of benefit to being able to set
> the limit much lower than what it currently defaults to today. We have a
> client that has a queue-type table that is updated very frequently. One
> of the fields is text, that is not updated as frequently. Keeping this
> table vacuumed well enough has proven to be problematic, because any
> delay to vacuuming quickly results in a very large amount of bloat.
> Moving that text field into a seperate table would most likely be a win.
> 
> Presumably this would need to be settable on at least a per-table basis.
> 
> Would adding such a variable be a good beginner TODO, or is it too
> invasive?

Well, we have now:
          ALTER TABLE ALTER [ COLUMN ] column     SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }

What else is needed?

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