On Wed, Jun 22, 2016 at 10:13 PM, Amit Kapila <amit.kapila16@gmail.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
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
