From eeaa7cb36c69af048f0321e4883864ebe2542429 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Wed, 22 Dec 2021 03:18:46 +0100 Subject: [PATCH 1/6] WAL-log individual sequence fetches --- src/backend/commands/sequence.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c index 72bfdc07a4..0f309d0a4e 100644 --- a/src/backend/commands/sequence.c +++ b/src/backend/commands/sequence.c @@ -52,6 +52,9 @@ * We don't want to log each fetching of a value from a sequence, * so we pre-log a few fetches in advance. In the event of * crash we can lose (skip over) as many values as we pre-logged. + * + * We only pre-log fetches in wal_level=minimal. For higher levels we + * WAL-log every individual sequence increment, as if this was 0. */ #define SEQ_LOG_VALS 32 @@ -666,11 +669,18 @@ nextval_internal(Oid relid, bool check_permissions) * WAL record to be written anyway, else replay starting from the * checkpoint would fail to advance the sequence past the logged values. * In this case we may as well fetch extra values. + * + * We only pre-log fetches in wal_level=minimal. For higher levels we + * WAL-log every individual sequence increment. */ if (log < fetch || !seq->is_called) { /* forced log to satisfy local demand for values */ - fetch = log = fetch + SEQ_LOG_VALS; + if (XLogIsNeeded()) + fetch = log = fetch; + else + fetch = log = fetch + SEQ_LOG_VALS; + logit = true; } else @@ -680,7 +690,11 @@ nextval_internal(Oid relid, bool check_permissions) if (PageGetLSN(page) <= redoptr) { /* last update of seq was before checkpoint */ - fetch = log = fetch + SEQ_LOG_VALS; + if (XLogIsNeeded()) + fetch = log = fetch; + else + fetch = log = fetch + SEQ_LOG_VALS; + logit = true; } } -- 2.31.1