Hi, I don't have any immediate feedback regarding this patch, but I'm wondering about one thing related to cancellations - we talk cancelling a query, but we really target a PID (or a particular backend, no matter how we identify it).
I occasionally want to only cancel a particular query, but I don't think that's really possible - the query may complete meanwhile, and the backend may even get used for a different user connection (e.g. with a connection pool)? Or am I missing something important? Anyway, I wonder if making the cancellation key longer (or variable length) might be useful for this too - it would allow including some sort of optional "query ID" in the request, not just the PID. (Maybe st_xact_start_timestamp would work?) Obviously, that's not up to this patch, but it's somewhat related. regards -- Tomas Vondra EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
