Thread: How much shared memory does Postgresql need per max_locks_per_transaction?

I have a Postgresql 10 database with about 300k tables in 23k schemas. I am trying to upgrade to Postgresql 13 using pg_upgradecluster. This is failing while attempting dump all the schemas:

pg_dump: error: query failed: ERROR:  out of shared memory

HINT:  You might need to increase max_locks_per_transaction.

pg_dump: error: query was: LOCK TABLE "a45119740"."activity_hrc" IN ACCESS SHARE MODE

Is setting max_locks_per_transaction to 300k something that can be done? I haven't been able to find anything explaining how much shared memory this might need. The machine has 64G of RAM.

(I understand that I need to change my db design .. I have been backing up one schema at a time until now so wasn't aware of this problem)

Thanks

David