Tom Lane wrote:
> Hannu Krosing <hannu@tm.ee> writes:
> > But if we would allow the scans to find the same keys twice without ill
> > effects (as was suggested earlier, for using btrees to index arrays),
>
> How is returning the same data twice not an "ill effect"?
>
> > then we could possibly 1) copy the key to the right 2) wait for all
> > right-to-left scans that have fallen between old and new values to pass
> > and only then 3) delete the "old left" key.
>
> How will you wait for scans that you know nothing of to go past?
> Especially when they are going to be blocked by your own write lock
> on the left page?
I think we should skip any pages where we can't get a lock.
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
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