On Sat, Feb 25, 2017 at 10:00 AM, Kohei KaiGai <kai...@kaigai.gr.jp> wrote: > I tried to add a description how custom-scan callbacks performs under the > executor, and when invoked roughly. > However, it is fundamentally not easy for most of people because it assumes > FDW/CSP author understand the overall behavior of optimizer / executor, not > only APIs specifications.
I think the statements about Shutdown only being useful in parallel mode aren't quite striking the right tone. In theory a node can hold any kind of resources and find it worthwhile to release them at shutdown time. I think we'll eventually find it useful to run shutdown callbacks in other cases as well - e.g. when a Limit has been filled. It's probably true that the undeniable need for this today is in the parallel query case, but I'd like to have this text read in a way that doesn't assert that this is the only possible use case, because I don't think it is. I rewrote the documentation along those lines a bit and committed this. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers