Re: [HACKERS] Optimizer fails?

David Gould wrote:
>
> > Now, let's note, that there has been only a few IO transfers by now. No
> > more than few pages. And we have tupple identifiers pointing us to 64
> > records. Now we may sort this tids in ascending order to optimise IO.
>
> But, we do not do this tid sort. It really isn't easy as you might have
> millions of tids, not just a few. Which would mean doing an external sort.
> This might be a nice thing to do, but it isn't there now as far as I know.

Using TID as (last) part of index key is on my TODO.
This will speed up vacuuming, get rid of all duplicate key
problems and give us feature above.

> To scan the index to get the tids for keys 0...63 will take two page
> reads: root page, leaf1.

+ meta page read first - to get root page block number.

Vadim