On Fri, Oct 13, 2023 at 2:03 PM Dilip Kumar <dilipbal...@gmail.com> wrote: > > On Fri, Oct 13, 2023 at 11:07 AM Amit Kapila <amit.kapil...@gmail.com> wrote: > > > > > But is this a problem? basically, we will set the > > > ShmemVariableCache->nextOid counter to the value that we want in the > > > IsBinaryUpgrade-specific function. And then the shutdown checkpoint > > > will flush that value to the control file and that is what we want no? > > > > > > > I think that can work. Basically, we need to do something like what > > SetNextObjectId() does and then let the shutdown checkpoint update the > > actual value in the control file. > > Right. > > > > I mean instead of resetwal directly modifying the control file we > > > will modify that value in the server using the binary_upgrade function > > > and then have that value flush to the disk by shutdown checkpoint. > > > > > > > True, the alternative to consider is to let pg_upgrade update the > > control file by itself with the required value of OID. The point I am > > slightly worried about doing via server-side function is that some > > online and or shutdown checkpoint can update other values in the > > control file as well whereas if we do via pg_upgrade, we can have > > better control over just updating the OID. > > Yeah, thats a valid point. >
But OTOH, just updating the control file via pg_upgrade may not be sufficient because we should keep the shutdown checkpoint record also updated with that value. See how pg_resetwal achieves it via RewriteControlFile() and WriteEmptyXLOG(). So, considering both the approaches it seems better to go with a server-side function as Robert suggested. -- With Regards, Amit Kapila.
