Re: INSERT ... ON CONFLICT {UPDATE | IGNORE}

Josh Berkus <josh@agliodbs.com> wrote:
> On 09/30/2014 07:15 AM, Kevin Grittner wrote:

>> At the risk of pushing people away from this POV, I'll point out
>> that this is somewhat similar to what we do for unlogged bulk loads
>> -- if all the conditions for doing it the fast way are present, we
>> do it the fast way; otherwise it still works, but slower.
>
> Except that switching between fast/slow bulk loads affects *only* the
> speed of loading, not the locking rules.  Having a statement silently
> take a full table lock when we were expecting it to be concurrent
> (because, for example, the index got rebuilt and someone forgot the
> UNIQUE) violates POLA from my perspective.

I would not think that an approach which took a full table lock to
implement the more general case would be accepted.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company