Hi, On 2018-07-30 16:59:16 +0900, Michael Paquier wrote: > + /* > + * Mark MyProc as owning this namespace which other processes can use to > + * decide if a temporary namespace is in use or not. Even if this is an > + * atomic operation, this can be safely done lock-less as no temporary > + * relations associated to it can be seen yet if scanning pg_class. > + */ > + MyProc->tempNamespaceId = namespaceId;
I can't parse this. "Even if this is an atomic operation, this can be safely done lock-less" - that seems like a contradictory sentence. Is there a "not" missing? Also, this seems like insufficient reasoning. What guarantees the visibility of the flag? You're going to have to talk about externally implied memory ordering here. Or add explicit barriers - the latter is probably preferrable. Greetings, Andres Freund
