From 8e87c95522d54fdacd77acf1c5b314968d3c7e68 Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Fri, 31 Mar 2023 10:38:39 -0400 Subject: [PATCH v16 1/3] Make vacuum's failsafe_active a global While vacuuming a table in failsafe mode, VacuumCostActive should not be re-enabled. This currently isn't a problem because vacuum cost parameters are only refreshed in between vacuuming tables and failsafe status is reset for every table. In preparation for allowing vacuum cost parameters to be updated more frequently, elevate LVRelState->failsafe_active to a global, VacuumFailsafeActive, which will be checked when determining whether or not to re-enable vacuum cost-related delays. Reviewed-by: Masahiko Sawada Reviewed-by: Daniel Gustafsson Reviewed-by: Kyotaro Horiguchi Discussion: https://www.postgresql.org/message-id/flat/CAAKRu_ZngzqnEODc7LmS1NH04Kt6Y9huSjz5pp7%2BDXhrjDA0gw%40mail.gmail.com --- src/backend/access/heap/vacuumlazy.c | 16 +++++++--------- src/backend/commands/vacuum.c | 15 +++++++++++++++ src/include/commands/vacuum.h | 1 + 3 files changed, 23 insertions(+), 9 deletions(-) diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index 639179aa46..2ba85bd3d6 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -153,8 +153,6 @@ typedef struct LVRelState bool aggressive; /* Use visibility map to skip? (disabled by DISABLE_PAGE_SKIPPING) */ bool skipwithvm; - /* Wraparound failsafe has been triggered? */ - bool failsafe_active; /* Consider index vacuuming bypass optimization? */ bool consider_bypass_optimization; @@ -391,7 +389,7 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, Assert(params->index_cleanup != VACOPTVALUE_UNSPECIFIED); Assert(params->truncate != VACOPTVALUE_UNSPECIFIED && params->truncate != VACOPTVALUE_AUTO); - vacrel->failsafe_active = false; + VacuumFailsafeActive = false; vacrel->consider_bypass_optimization = true; vacrel->do_index_vacuuming = true; vacrel->do_index_cleanup = true; @@ -709,7 +707,7 @@ heap_vacuum_rel(Relation rel, VacuumParams *params, } else { - if (!vacrel->failsafe_active) + if (!VacuumFailsafeActive) appendStringInfoString(&buf, _("index scan bypassed: ")); else appendStringInfoString(&buf, _("index scan bypassed by failsafe: ")); @@ -2293,7 +2291,7 @@ lazy_vacuum(LVRelState *vacrel) * vacuuming or heap vacuuming. This VACUUM operation won't end up * back here again. */ - Assert(vacrel->failsafe_active); + Assert(VacuumFailsafeActive); } /* @@ -2374,7 +2372,7 @@ lazy_vacuum_all_indexes(LVRelState *vacrel) */ Assert(vacrel->num_index_scans > 0 || vacrel->dead_items->num_items == vacrel->lpdead_items); - Assert(allindexes || vacrel->failsafe_active); + Assert(allindexes || VacuumFailsafeActive); /* * Increase and report the number of index scans. @@ -2616,12 +2614,12 @@ static bool lazy_check_wraparound_failsafe(LVRelState *vacrel) { /* Don't warn more than once per VACUUM */ - if (vacrel->failsafe_active) + if (VacuumFailsafeActive) return true; if (unlikely(vacuum_xid_failsafe_check(&vacrel->cutoffs))) { - vacrel->failsafe_active = true; + VacuumFailsafeActive = true; /* * Abandon use of a buffer access strategy to allow use of all of @@ -2820,7 +2818,7 @@ should_attempt_truncation(LVRelState *vacrel) { BlockNumber possibly_freeable; - if (!vacrel->do_rel_truncate || vacrel->failsafe_active || + if (!vacrel->do_rel_truncate || VacuumFailsafeActive || old_snapshot_threshold >= 0) return false; diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index da85330ef4..c74b21fce9 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -72,6 +72,21 @@ int vacuum_multixact_freeze_table_age; int vacuum_failsafe_age; int vacuum_multixact_failsafe_age; +/* + * VacuumFailsafeActive is a defined as a global so that we can determine + * whether or not to re-enable cost-based vacuum delay when vacuuming a table. + * If failsafe mode has been engaged, we will not re-enable cost-based delay + * for the table until after vacuuming has completed, regardless of other + * settings. + * + * Only VACUUM code should inspect this variable and only table access methods + * should set it to true. In Table AM-agnostic VACUUM code, this variable is + * inspected to determine whether or not to allow cost-based delays. Table AMs + * are free to set it if they desire this behavior, but it is false by default + * and reset to false in between vacuuming each relation. + */ +bool VacuumFailsafeActive = false; + /* * Variables for cost-based parallel vacuum. See comments atop * compute_parallel_delay to understand how it works. diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h index bdfd96cfec..7219c6ba9c 100644 --- a/src/include/commands/vacuum.h +++ b/src/include/commands/vacuum.h @@ -306,6 +306,7 @@ extern PGDLLIMPORT pg_atomic_uint32 *VacuumSharedCostBalance; extern PGDLLIMPORT pg_atomic_uint32 *VacuumActiveNWorkers; extern PGDLLIMPORT int VacuumCostBalanceLocal; +extern PGDLLIMPORT bool VacuumFailsafeActive; /* in commands/vacuum.c */ extern void ExecVacuum(ParseState *pstate, VacuumStmt *vacstmt, bool isTopLevel); -- 2.37.2