On Tue, Nov 28, 2023 at 10:58 PM Hayato Kuroda (Fujitsu) <kuroda.hay...@fujitsu.com> wrote: > > Dear Sawada-san, > > > On Tue, Nov 28, 2023 at 7:04 PM Hayato Kuroda (Fujitsu) > > <kuroda.hay...@fujitsu.com> wrote: > > > > > > > > > Yeah, we followed binary_upgrade_create_empty_extension(). Also, we set as > > > un-strict to keep a caller function simpler. > > > > > > Currently get_old_cluster_logical_slot_infos() executes a query and it > > > contains > > > binary_upgrade_logical_slot_has_caught_up(). In pg_upgrade layer, we > > assumed > > > either true or false is returned. > > > > > > But if proisstrict is changed true, we must handle the case when NULL is > > returned. > > > It is small but backseat operation. > > > > Which cases are you concerned pg_upgrade could pass NULL to > > binary_upgrade_logical_slot_has_caught_up()? > > Actually, we do not expect that it won't input NULL. IIUC all of slots have > slot_name, and subquery uses its name. But will it be kept forever? I think we > can avoid any risk. > > > I've not tested it yet but even if it returns NULL, perhaps > > get_old_cluster_logical_slot_infos() would still set curr->caught_up > > to false, no? > > Hmm. I checked the C99 specification [1] of strcmp, but it does not define the > case when the NULL is input. So it depends implementation.
I think PQgetvalue() returns an empty string if the result value is null. Regards, -- Masahiko Sawada Amazon Web Services: https://aws.amazon.com
