Save prune cycles by consistently clearing prune hints on all-visible pages
All-visible pages can't contain prunable tuples. We already clear the prune hint (pd_prune_xid) during pruning of all-visible pages, but we were not doing so in vacuum phase three, nor initializing it for all-frozen pages created by COPY FREEZE, and we were not clearing it on standbys. Because page hints are not WAL-logged, pages on a standby carry stale pd_prune_xid values. After promotion, that stale hint triggers unnecessary on-access pruning. Fix this by clearing the prune hint everywhere we currently mark a heap page all-visible. Clearing it when setting PD_ALL_VISIBLE ensures no extra overhead. Author: Melanie Plageman <[email protected]> Reviewed-by: Andres Freund <[email protected]> Discussion: https://postgr.es/m/flat/CAAKRu_b-BMOyu0X-0jc_8bWNSbQ5K6JTEueayEhcQuw-OkCSKg%40mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/8b9d42bf6bd29b855a6bee21aa6010c070980086 Modified Files -------------- src/backend/access/heap/heapam.c | 1 + src/backend/access/heap/heapam_xlog.c | 7 +++++++ src/backend/access/heap/vacuumlazy.c | 3 +++ 3 files changed, 11 insertions(+)
