manoj kathar <manojkathar3(at)gmail(dot)com> writes:
> We are performing the PostgreSQL DB upgrade using pg_upgrade from 9.6 to
> 12.5 on the production server.
What is the rationale for choosing 12.5? The current v12-branch release
is 12.11 (and 12.12 will be out next week). So you're missing nearly
two years' worth of bug fixes. A quick look through the release notes
shows at least one pg_upgrade fix that could be relevant, from 12.8:
Make <application>pg_upgrade</application> carry forward the old
installation's <literal>oldestXID</literal> value (Bertrand Drouvot)
regards, tom lane