The purpose is to concat new data onto existing values of c: UPDATE tbl SET c = c || new_data.c FROM ( [...] ) AS new_data WHERE tbl.id = new_data.id It appears to have a race condition: t0: Query A starts subquery t1: Query A starts self-join t2. Query A starts UPDATE with data from self-join and subquery t3. Query B starts subquery t4. Query B starts self-join (note: data from t1!) [...] tN. Query A finishes UPDATE tN+1. Query B finishes UPDATE, missing any new_data from Query A My assumption is that t1 and t4 (the self-joins) use SELECT but not SELECT FOR UPDATE. If they did, I think the race condition would go away. Did I analyze that right? Thanks! -- Seamus Abshere, SCEA https://github.com/seamusabshere https://linkedin.com/in/seamusabshere https://www.faraday.io -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
