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Separate multixact freezing parameters from xid's

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Previously we were piggybacking on transaction ID parameters to freeze
multixacts; but since there isn't necessarily any relationship between
rates of Xid and multixact consumption, this turns out not to be a good
idea.

Therefore, we now have multixact-specific freezing parameters:

vacuum_multixact_freeze_min_age: when to remove multis as we come across
them in vacuum (default to 5 million, i.e. early in comparison to Xid's
default of 50 million)

vacuum_multixact_freeze_table_age: when to force whole-table scans
instead of scanning only the pages marked as not all visible in
visibility map (default to 150 million, same as for Xids).  Whichever of
both which reaches the 150 million mark earlier will cause a whole-table
scan.

autovacuum_multixact_freeze_max_age: when for cause emergency,
uninterruptible whole-table scans (default to 400 million, double as
that for Xids).  This means there shouldn't be more frequent emergency
vacuuming than previously, unless multixacts are being used very
rapidly.

Backpatch to 9.3 where multixacts were made to persist enough to require
freezing.  To avoid an ABI break in 9.3, VacuumStmt has a couple of
fields in an unnatural place, and StdRdOptions is split in two so that
the newly added fields can go at the end.

Patch by me, reviewed by Robert Haas, with additional input from Andres
Freund and Tom Lane.
This commit is contained in:
Alvaro Herrera
2014-02-13 19:30:30 -03:00
parent ca1c171817
commit fb47de2be6
20 changed files with 446 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

71
src/backend/postmaster/autovacuum.c
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@@ -116,6 +116,7 @@ double autovacuum_vac_scale;
int autovacuum_anl_thresh;
double autovacuum_anl_scale;
int autovacuum_freeze_max_age;
int autovacuum_multixact_freeze_max_age;
int autovacuum_vac_cost_delay;
int autovacuum_vac_cost_limit;
@@ -144,6 +145,8 @@ static MultiXactId recentMulti;
/* Default freeze ages to use for autovacuum (varies by database) */
static int default_freeze_min_age;
static int default_freeze_table_age;
static int default_multixact_freeze_min_age;
static int default_multixact_freeze_table_age;
/* Memory context for long-lived data */
static MemoryContext AutovacMemCxt;
@@ -185,6 +188,8 @@ typedef struct autovac_table
bool at_doanalyze;
int at_freeze_min_age;
int at_freeze_table_age;
int at_multixact_freeze_min_age;
int at_multixact_freeze_table_age;
int at_vacuum_cost_delay;
int at_vacuum_cost_limit;
bool at_wraparound;
@@ -297,6 +302,7 @@ static void FreeWorkerInfo(int code, Datum arg);
static autovac_table *table_recheck_autovac(Oid relid, HTAB *table_toast_map,
TupleDesc pg_class_desc);
static void relation_needs_vacanalyze(Oid relid, AutoVacOpts *relopts,
AutoVacOpts2 *relopts2,
Form_pg_class classForm,
PgStat_StatTabEntry *tabentry,
bool *dovacuum, bool *doanalyze, bool *wraparound);
@@ -304,7 +310,8 @@ static void relation_needs_vacanalyze(Oid relid, AutoVacOpts *relopts,
static void autovacuum_do_vac_analyze(autovac_table *tab,
BufferAccessStrategy bstrategy);
static AutoVacOpts *extract_autovac_opts(HeapTuple tup,
TupleDesc pg_class_desc);
TupleDesc pg_class_desc,
AutoVacOpts2 **opts2);
static PgStat_StatTabEntry *get_pgstat_tabentry_relid(Oid relid, bool isshared,
PgStat_StatDBEntry *shared,
PgStat_StatDBEntry *dbentry);
@@ -1129,7 +1136,7 @@ do_start_worker(void)
/* Also determine the oldest datminmxid we will consider. */
recentMulti = ReadNextMultiXactId();
multiForceLimit = recentMulti - autovacuum_freeze_max_age;
multiForceLimit = recentMulti - autovacuum_multixact_freeze_max_age;
if (multiForceLimit < FirstMultiXactId)
multiForceLimit -= FirstMultiXactId;
@@ -1955,11 +1962,15 @@ do_autovacuum(void)
{
default_freeze_min_age = 0;
default_freeze_table_age = 0;
default_multixact_freeze_min_age = 0;
default_multixact_freeze_table_age = 0;
}
else
{
default_freeze_min_age = vacuum_freeze_min_age;
default_freeze_table_age = vacuum_freeze_table_age;
default_multixact_freeze_min_age = vacuum_multixact_freeze_min_age;
default_multixact_freeze_table_age = vacuum_multixact_freeze_table_age;
}
ReleaseSysCache(tuple);
@@ -2011,6 +2022,7 @@ do_autovacuum(void)
Form_pg_class classForm = (Form_pg_class) GETSTRUCT(tuple);
PgStat_StatTabEntry *tabentry;
AutoVacOpts *relopts;
AutoVacOpts2 *relopts2;
Oid relid;
bool dovacuum;
bool doanalyze;
@@ -2023,12 +2035,12 @@ do_autovacuum(void)
relid = HeapTupleGetOid(tuple);
/* Fetch reloptions and the pgstat entry for this table */
relopts = extract_autovac_opts(tuple, pg_class_desc);
relopts = extract_autovac_opts(tuple, pg_class_desc, &relopts2);
tabentry = get_pgstat_tabentry_relid(relid, classForm->relisshared,
shared, dbentry);
/* Check if it needs vacuum or analyze */
relation_needs_vacanalyze(relid, relopts, classForm, tabentry,
relation_needs_vacanalyze(relid, relopts, relopts2, classForm, tabentry,
&dovacuum, &doanalyze, &wraparound);
/*
@@ -2125,6 +2137,7 @@ do_autovacuum(void)
PgStat_StatTabEntry *tabentry;
Oid relid;
AutoVacOpts *relopts = NULL;
AutoVacOpts2 *relopts2 = NULL;
bool dovacuum;
bool doanalyze;
bool wraparound;
@@ -2141,7 +2154,7 @@ do_autovacuum(void)
* fetch reloptions -- if this toast table does not have them, try the
* main rel
*/
relopts = extract_autovac_opts(tuple, pg_class_desc);
relopts = extract_autovac_opts(tuple, pg_class_desc, &relopts2);
if (relopts == NULL)
{
av_relation *hentry;
@@ -2156,7 +2169,7 @@ do_autovacuum(void)
tabentry = get_pgstat_tabentry_relid(relid, classForm->relisshared,
shared, dbentry);
relation_needs_vacanalyze(relid, relopts, classForm, tabentry,
relation_needs_vacanalyze(relid, relopts, relopts2, classForm, tabentry,
&dovacuum, &doanalyze, &wraparound);
/* ignore analyze for toast tables */
@@ -2397,12 +2410,17 @@ deleted:
*
* Given a relation's pg_class tuple, return the AutoVacOpts portion of
* reloptions, if set; otherwise, return NULL.
*
* 9.3 kludge: return the separate "AutoVacOpts2" part too.
*/
static AutoVacOpts *
extract_autovac_opts(HeapTuple tup, TupleDesc pg_class_desc)
extract_autovac_opts(HeapTuple tup, TupleDesc pg_class_desc, AutoVacOpts2 **opts2)
{
bytea *relopts;
AutoVacOpts *av;
AutoVacOpts2 *av2;
*opts2 = NULL;
Assert(((Form_pg_class) GETSTRUCT(tup))->relkind == RELKIND_RELATION ||
((Form_pg_class) GETSTRUCT(tup))->relkind == RELKIND_MATVIEW ||
@@ -2414,6 +2432,11 @@ extract_autovac_opts(HeapTuple tup, TupleDesc pg_class_desc)
av = palloc(sizeof(AutoVacOpts));
memcpy(av, &(((StdRdOptions *) relopts)->autovacuum), sizeof(AutoVacOpts));
av2 = palloc(sizeof(AutoVacOpts2));
memcpy(av2, &(((StdRdOptions *) relopts)->autovacuum2), sizeof(AutoVacOpts2));
*opts2 = av2;
pfree(relopts);
return av;
@@ -2465,6 +2488,7 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
PgStat_StatDBEntry *dbentry;
bool wraparound;
AutoVacOpts *avopts;
AutoVacOpts2 *avopts2;
/* use fresh stats */
autovac_refresh_stats();
@@ -2482,7 +2506,7 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
* Get the applicable reloptions. If it is a TOAST table, try to get the
* main table reloptions if the toast table itself doesn't have.
*/
avopts = extract_autovac_opts(classTup, pg_class_desc);
avopts = extract_autovac_opts(classTup, pg_class_desc, &avopts2);
if (classForm->relkind == RELKIND_TOASTVALUE &&
avopts == NULL && table_toast_map != NULL)
{
@@ -2498,7 +2522,7 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
tabentry = get_pgstat_tabentry_relid(relid, classForm->relisshared,
shared, dbentry);
relation_needs_vacanalyze(relid, avopts, classForm, tabentry,
relation_needs_vacanalyze(relid, avopts, avopts2, classForm, tabentry,
&dovacuum, &doanalyze, &wraparound);
/* ignore ANALYZE for toast tables */
@@ -2510,6 +2534,8 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
{
int freeze_min_age;
int freeze_table_age;
int multixact_freeze_min_age;
int multixact_freeze_table_age;
int vac_cost_limit;
int vac_cost_delay;
@@ -2543,12 +2569,24 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
? avopts->freeze_table_age
: default_freeze_table_age;
multixact_freeze_min_age = (avopts2 &&
avopts2->multixact_freeze_min_age >= 0)
? avopts2->multixact_freeze_min_age
: default_multixact_freeze_min_age;
multixact_freeze_table_age = (avopts2 &&
avopts2->multixact_freeze_table_age >= 0)
? avopts2->multixact_freeze_table_age
: default_multixact_freeze_table_age;
tab = palloc(sizeof(autovac_table));
tab->at_relid = relid;
tab->at_dovacuum = dovacuum;
tab->at_doanalyze = doanalyze;
tab->at_freeze_min_age = freeze_min_age;
tab->at_freeze_table_age = freeze_table_age;
tab->at_multixact_freeze_min_age = multixact_freeze_min_age;
tab->at_multixact_freeze_table_age = multixact_freeze_table_age;
tab->at_vacuum_cost_limit = vac_cost_limit;
tab->at_vacuum_cost_delay = vac_cost_delay;
tab->at_wraparound = wraparound;
@@ -2567,7 +2605,7 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
*
* Check whether a relation needs to be vacuumed or analyzed; return each into
* "dovacuum" and "doanalyze", respectively. Also return whether the vacuum is
* being forced because of Xid wraparound.
* being forced because of Xid or multixact wraparound.
*
* relopts is a pointer to the AutoVacOpts options (either for itself in the
* case of a plain table, or for either itself or its parent table in the case
@@ -2586,7 +2624,8 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
* analyze. This is asymmetric to the VACUUM case.
*
* We also force vacuum if the table's relfrozenxid is more than freeze_max_age
* transactions back.
* transactions back, and if its relminmxid is more than
* multixact_freeze_max_age multixacts back.
*
* A table whose autovacuum_enabled option is false is
* automatically skipped (unless we have to vacuum it due to freeze_max_age).
@@ -2601,6 +2640,7 @@ table_recheck_autovac(Oid relid, HTAB *table_toast_map,
static void
relation_needs_vacanalyze(Oid relid,
AutoVacOpts *relopts,
AutoVacOpts2 *relopts2,
Form_pg_class classForm,
PgStat_StatTabEntry *tabentry,
/* output params below */
@@ -2628,6 +2668,7 @@ relation_needs_vacanalyze(Oid relid,
/* freeze parameters */
int freeze_max_age;
int multixact_freeze_max_age;
TransactionId xidForceLimit;
MultiXactId multiForceLimit;
@@ -2661,6 +2702,10 @@ relation_needs_vacanalyze(Oid relid,
? Min(relopts->freeze_max_age, autovacuum_freeze_max_age)
: autovacuum_freeze_max_age;
multixact_freeze_max_age = (relopts2 && relopts2->multixact_freeze_max_age >= 0)
? Min(relopts2->multixact_freeze_max_age, autovacuum_multixact_freeze_max_age)
: autovacuum_multixact_freeze_max_age;
av_enabled = (relopts ? relopts->enabled : true);
/* Force vacuum if table is at risk of wraparound */
@@ -2672,7 +2717,7 @@ relation_needs_vacanalyze(Oid relid,
xidForceLimit));
if (!force_vacuum)
{
multiForceLimit = recentMulti - autovacuum_freeze_max_age;
multiForceLimit = recentMulti - multixact_freeze_max_age;
if (multiForceLimit < FirstMultiXactId)
multiForceLimit -= FirstMultiXactId;
force_vacuum = MultiXactIdPrecedes(classForm->relminmxid,
@@ -2754,6 +2799,8 @@ autovacuum_do_vac_analyze(autovac_table *tab,
vacstmt.options |= VACOPT_ANALYZE;
vacstmt.freeze_min_age = tab->at_freeze_min_age;
vacstmt.freeze_table_age = tab->at_freeze_table_age;
vacstmt.multixact_freeze_min_age = tab->at_multixact_freeze_min_age;
vacstmt.multixact_freeze_table_age = tab->at_multixact_freeze_table_age;
/* we pass the OID, but might need this anyway for an error message */
vacstmt.relation = &rangevar;
vacstmt.va_cols = NIL;