On Fri, Jan 13, 2012 at 8:02 PM, Noah Misch <n...@leadboat.com> wrote: > Simon spoke to the FPI side of the question. For heap pages, the > XLOG_HEAP_NEWPAGE consumers are CLUSTER, VACUUM FULL and ALTER TABLE SET > TABLESPACE. For the last, we will have already logged any PD_ALL_VISIBLE bits > through normal channels. CLUSTER and VACUUM FULL never set PD_ALL_VISIBLE or > visibility map bits. When, someday, they do, we might emit a separate WAL > record to force the recovery conflict. However, CLUSTER/VACUUM FULL already > remove tuples still-visible to standby snapshots without provoking a recovery > conflict. (Again only with hot_standby_feedback=off.)
Is the big about CLUSTER/VACUUM FULL a preexisting bug? If not, why not? Other than that, it seems like we might be converging on a workable solution: if hot_standby_feedback=off, disable index-only scans for snapshots taken during recovery; if hot_standby_feedback=on, generate recovery conflicts when a snapshot's xmin precedes the youngest xmin on a page marked all-visible, but allow the use of index-only scans, and allow sequential scans to trust PD_ALL_VISIBLE. Off the top of my head, I don't see a hole in that logic... -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
