The "equality implies image equality" opclass infrastructure disallowed deduplication in system catalog indexes and TOAST indexes before now. That seemed like the right approach back when the infrastructure was added by commit 612a1ab7, since ALTER INDEX cannot set deduplicate_items to 'off' (due to an old implementation restriction). But that decision now seems arbitrary at best. Remove special case handling implementing this policy.
No catversion bump, since existing catalog indexes will still work.
Author: Peter Geoghegan Discussion: https://postgr.es/m/CAH2-Wz=rYQHFaJ3WYBdK=xgwxKzaiGMSSrh-ZCREa-pS-7Zjew@mail.gmail.com
2903f1404d Enable deduplication in system catalog indexes.
src/backend/access/nbtree/nbtutils.c | 12 ------------
1 file changed, 12 deletions(-)