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Make vacuum failsafe_active globally visible 

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.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAAKRu_ZngzqnEODc7LmS1NH04Kt6Y9huSjz5pp7%2BDXhrjDA0gw%40mail.gmail.com
This commit is contained in:
Daniel Gustafsson 2023-04-07 00:54:08 +02:00
parent 5499706bdf
commit 71a825194f
3 changed files with 23 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
src/backend/access/heap/vacuumlazy.c
View File

@ -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;

15
src/backend/commands/vacuum.c
View File

@ -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.

1
src/include/commands/vacuum.h
View File

@ -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);