On Fri, Aug 25, 2023 at 9:09 AM Peter Smith <smithpb2...@gmail.com> wrote: > > On Thu, Aug 24, 2023 at 8:18 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > > > On Thu, Aug 24, 2023 at 1:20 PM Alvaro Herrera <alvhe...@alvh.no-ip.org> > > wrote: > > > > > > On 2023-Aug-24, Amit Kapila wrote: > > > > > > > On Wed, Aug 23, 2023 at 1:31 PM Alvaro Herrera > > > > <alvhe...@alvh.no-ip.org> wrote: > > > > > > > > Hmm, I think if worker->in_use is false, we shouldn't consult the rest > > > > > of the struct at all, so I propose to add the attached 0001 as a > > > > > minimal > > > > > fix. > > > > > > > > I think that way we may need to add the check for in_use before > > > > accessing each of the LogicalRepWorker struct fields or form some rule > > > > about which fields (or places) are okay to access without checking > > > > in_use field. > > > > > > As far as I realize, we have that rule already. It's only a few > > > relatively new places that have broken it. I understand that the in_use > > > concept comes from the one of the same name in ReplicationSlot, except > > > that it is not at all documented in worker_internal.h. > > > > > > So I propose we do both: apply Zhijie's patch and my 0001 now; and > > > somebody gets to document the locking design for LogicalRepWorker. > > > > > > > Agreed. > > Both of these patches (Hou-san's expedient resetting of the worker > type, Alvaro's 0001 putting the 'in_use' check within the isXXXWorker > type macros) appear to be blending the concept of "type" with whether > the worker is "alive" or not, which I am not sure is a good thing. IMO > the type is the type forever, so I felt type should get assigned only > once when the worker is "born". For example, a dead horse is still a > horse. >
I think it is important to have a alive check before accessing the worker type as we are doing for some of the other fields. For example, see the usage of in_use flag in the function logicalrep_worker_find(). The usage of parallel apply workers doesn't consider the use of in_use flag where as other worker types would first check in_use flag. -- With Regards, Amit Kapila.
