Re: [HACKERS] Predicate Locks for writes?

On Sat, Oct 7, 2017 at 7:26 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
> PredicateLockTuple() specifically avoids adding an SIRead lock if the
> tuple already has a write lock on it, so surely it must also be
> correct to skip the SIRead lock if we are just about to update the
> row?

I wonder if there's a race condition.  Can someone else read/update
the tuple between the time when we would've taken the SIRead lock and
the time when we would have gotten the actual tuple lock?

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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