Re: Hash Indexes

On Wed, Jun 22, 2016 at 10:13 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>> A scan that has seen the flag won't look at the
>> tuple in any case.
>
> Why so? Assume that scan started on new bucket where
> split-in-progress flag was set, now it will not look at tuples that
> are marked as moved-by-split in this bucket, as it will assume to find
> all such tuples in old bucket. Now, if allow Vacuum or someone else
> to remove tuples from old with just an Exclusive lock, it is quite
> possible that scan miss the tuple in old bucket which got removed by
> vacuum.

Oh, you're right. So we really need to CLEAR the split-in-progress
flag before removing any tuples from the old bucket. Does that sound
right?

--
Robert Haas
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