Re: UPSERT wiki page, and SQL MERGE syntax - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: UPSERT wiki page, and SQL MERGE syntax
Date
Msg-id CAM3SWZQB8AKj6WKu7ErUk67a2EW7gwoy7tJmotYX7ugqFjSEQQ@mail.gmail.com
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In response to Re: UPSERT wiki page, and SQL MERGE syntax  (Peter Geoghegan <pg@heroku.com>)
List pgsql-hackers
On Fri, Oct 3, 2014 at 3:42 PM, Peter Geoghegan <pg@heroku.com> wrote:
>> We routinely pick very
>> different plans based on the presence or absence of an index, and
>> we use special snapshots in the course of executing many DML
>> statements (if FK triggers are fired)

Apart from FK snapshots, we also use dirty snapshots for unique index
enforcement, obviously. That doesn't mean that it's the "command/xact
snapshot", though. It's just a special constraint enforcement
mechanism.


-- 
Peter Geoghegan



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