I've attached a new patch to show roughly what I think this new GUC should
look like. I'm hoping this sparks more discussion, if nothing else.
On Tue, Jun 18, 2024 at 12:36:42PM +0200, Frédéric Yhuel wrote:
> By the way, I wonder if there were any off-list discussions after Robert's
> conference at PGConf.dev (and I'm waiting for the video of the conf).
I don't recall any discussions about this idea, but Robert did briefly
mention it in his talk [0].
[0] https://www.youtube.com/watch?v=RfTD-Twpvac
--
nathan
>From ccfaee370835d755b663357bf139fea729a5f454 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nat...@postgresql.org>
Date: Wed, 7 Aug 2024 16:22:37 -0500
Subject: [PATCH v2 1/1] autovacuum_max_threshold
---
doc/src/sgml/config.sgml | 24 +++++++++++++++++++
doc/src/sgml/ref/create_table.sgml | 15 ++++++++++++
src/backend/access/common/reloptions.c | 11 +++++++++
src/backend/postmaster/autovacuum.c | 11 +++++++++
src/backend/utils/misc/guc_tables.c | 9 +++++++
src/backend/utils/misc/postgresql.conf.sample | 2 ++
src/bin/psql/tab-complete.c | 2 ++
src/include/postmaster/autovacuum.h | 1 +
src/include/utils/rel.h | 1 +
9 files changed, 76 insertions(+)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index a1a1d58a43..10855b0e19 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -8615,6 +8615,30 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH
csv;
</listitem>
</varlistentry>
+ <varlistentry id="guc-autovacuum-max-threshold"
xreflabel="autovacuum_max_threshold">
+ <term><varname>autovacuum_max_threshold</varname> (<type>integer</type>)
+ <indexterm>
+ <primary><varname>autovacuum_max_threshold</varname></primary>
+ <secondary>configuration parameter</secondary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Specifies the maximum number of updated or deleted tuples needed to
+ trigger a <command>VACUUM</command> in any one table, i.e., a cap on
+ the value calculated with
+ <varname>autovacuum_vacuum_threshold</varname> and
+ <varname>autovacuum_vacuum_scale_factor</varname>. The default is
+ 100,000,000 tuples. If -1 is specified, autovacuum will not enforce a
+ maximum number of updated or deleted tuples that will trigger a
+ <command>VACUUM</command> operation. This parameter can only be set in
+ the <filename>postgresql.conf</filename> file or on the server command
+ line; but the setting can be overridden for individual tables by
+ changing storage parameters.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-autovacuum-vacuum-insert-threshold"
xreflabel="autovacuum_vacuum_insert_threshold">
<term><varname>autovacuum_vacuum_insert_threshold</varname>
(<type>integer</type>)
<indexterm>
diff --git a/doc/src/sgml/ref/create_table.sgml
b/doc/src/sgml/ref/create_table.sgml
index 93b3f664f2..19b5ea7421 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -1596,6 +1596,21 @@ WITH ( MODULUS <replaceable
class="parameter">numeric_literal</replaceable>, REM
</listitem>
</varlistentry>
+ <varlistentry id="reloption-autovacuum-max-threshold"
xreflabel="autovacuum_max_threshold">
+ <term><literal>autovacuum_max_threshold</literal>,
<literal>toast.autovacuum_max_threshold</literal> (<type>integer</type>)
+ <indexterm>
+ <primary><varname>autovacuum_max_threshold</varname></primary>
+ <secondary>storage parameter</secondary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Per-table value for <xref linkend="guc-autovacuum-max-threshold"/>
+ parameter.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="reloption-autovacuum-vacuum-scale-factor"
xreflabel="autovacuum_vacuum_scale_factor">
<term><literal>autovacuum_vacuum_scale_factor</literal>,
<literal>toast.autovacuum_vacuum_scale_factor</literal> (<type>floating
point</type>)
<indexterm>
diff --git a/src/backend/access/common/reloptions.c
b/src/backend/access/common/reloptions.c
index 49fd35bfc5..c18ee4c497 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -231,6 +231,15 @@ static relopt_int intRelOpts[] =
},
-1, 0, INT_MAX
},
+ {
+ {
+ "autovacuum_max_threshold",
+ "Maximum number of tuple updates or deletes prior to
vacuum",
+ RELOPT_KIND_HEAP | RELOPT_KIND_TOAST,
+ ShareUpdateExclusiveLock
+ },
+ -1, 0, INT_MAX
+ },
{
{
"autovacuum_vacuum_insert_threshold",
@@ -1843,6 +1852,8 @@ default_reloptions(Datum reloptions, bool validate,
relopt_kind kind)
offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts,
enabled)},
{"autovacuum_vacuum_threshold", RELOPT_TYPE_INT,
offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts,
vacuum_threshold)},
+ {"autovacuum_max_threshold", RELOPT_TYPE_INT,
+ offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts,
vacuum_max_threshold)},
{"autovacuum_vacuum_insert_threshold", RELOPT_TYPE_INT,
offsetof(StdRdOptions, autovacuum) + offsetof(AutoVacOpts,
vacuum_ins_threshold)},
{"autovacuum_analyze_threshold", RELOPT_TYPE_INT,
diff --git a/src/backend/postmaster/autovacuum.c
b/src/backend/postmaster/autovacuum.c
index 4e4a0ccbef..d43d48abc8 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -119,6 +119,7 @@ int autovacuum_max_workers;
int autovacuum_work_mem = -1;
int autovacuum_naptime;
int autovacuum_vac_thresh;
+int autovacuum_max_thresh;
double autovacuum_vac_scale;
int autovacuum_vac_ins_thresh;
double autovacuum_vac_ins_scale;
@@ -2887,6 +2888,8 @@ recheck_relation_needs_vacanalyze(Oid relid,
* threshold. This threshold is calculated as
*
* threshold = vac_base_thresh + vac_scale_factor * reltuples
+ * if (threshold > vac_max_thresh)
+ * threshold = vac_max_thres;
*
* For analyze, the analysis done is that the number of tuples inserted,
* deleted and updated since the last analyze exceeds a threshold calculated
@@ -2925,6 +2928,7 @@ relation_needs_vacanalyze(Oid relid,
/* constants from reloptions or GUC variables */
int vac_base_thresh,
+ vac_max_thresh,
vac_ins_base_thresh,
anl_base_thresh;
float4 vac_scale_factor,
@@ -2966,6 +2970,10 @@ relation_needs_vacanalyze(Oid relid,
? relopts->vacuum_threshold
: autovacuum_vac_thresh;
+ vac_max_thresh = (relopts && relopts->vacuum_max_threshold >= 0)
+ ? relopts->vacuum_max_threshold
+ : autovacuum_max_thresh;
+
vac_ins_scale_factor = (relopts && relopts->vacuum_ins_scale_factor >=
0)
? relopts->vacuum_ins_scale_factor
: autovacuum_vac_ins_scale;
@@ -3039,6 +3047,9 @@ relation_needs_vacanalyze(Oid relid,
reltuples = 0;
vacthresh = (float4) vac_base_thresh + vac_scale_factor *
reltuples;
+ if (vac_max_thresh >= 0 && vacthresh > (float4) vac_max_thresh)
+ vacthresh = (float4) vac_max_thresh;
+
vacinsthresh = (float4) vac_ins_base_thresh +
vac_ins_scale_factor * reltuples;
anlthresh = (float4) anl_base_thresh + anl_scale_factor *
reltuples;
diff --git a/src/backend/utils/misc/guc_tables.c
b/src/backend/utils/misc/guc_tables.c
index c0a52cdcc3..9aae183786 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -3403,6 +3403,15 @@ struct config_int ConfigureNamesInt[] =
50, 0, INT_MAX,
NULL, NULL, NULL
},
+ {
+ {"autovacuum_max_threshold", PGC_SIGHUP, AUTOVACUUM,
+ gettext_noop("Maximum number of tuple updates or
deletes prior to vacuum."),
+ NULL
+ },
+ &autovacuum_max_thresh,
+ 100000000, -1, INT_MAX,
+ NULL, NULL, NULL
+ },
{
{"autovacuum_vacuum_insert_threshold", PGC_SIGHUP, AUTOVACUUM,
gettext_noop("Minimum number of tuple inserts prior to
vacuum, or -1 to disable insert vacuums."),
diff --git a/src/backend/utils/misc/postgresql.conf.sample
b/src/backend/utils/misc/postgresql.conf.sample
index 9ec9f97e92..e7cec694f3 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -663,6 +663,8 @@
#autovacuum_naptime = 1min # time between autovacuum runs
#autovacuum_vacuum_threshold = 50 # min number of row updates before
# vacuum
+#autovacuum_max_threshold = 100000000 # max number of row updates before
+ # vacuum
#autovacuum_vacuum_insert_threshold = 1000 # min number of row inserts
# before vacuum; -1 disables
insert
# vacuums
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 024469474d..f3ce76e23d 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1295,6 +1295,7 @@ static const char *const table_storage_parameters[] = {
"autovacuum_freeze_max_age",
"autovacuum_freeze_min_age",
"autovacuum_freeze_table_age",
+ "autovacuum_max_threshold",
"autovacuum_multixact_freeze_max_age",
"autovacuum_multixact_freeze_min_age",
"autovacuum_multixact_freeze_table_age",
@@ -1311,6 +1312,7 @@ static const char *const table_storage_parameters[] = {
"toast.autovacuum_freeze_max_age",
"toast.autovacuum_freeze_min_age",
"toast.autovacuum_freeze_table_age",
+ "toast.autovacuum_max_threshold",
"toast.autovacuum_multixact_freeze_max_age",
"toast.autovacuum_multixact_freeze_min_age",
"toast.autovacuum_multixact_freeze_table_age",
diff --git a/src/include/postmaster/autovacuum.h
b/src/include/postmaster/autovacuum.h
index cae1e8b329..efbab7bfa9 100644
--- a/src/include/postmaster/autovacuum.h
+++ b/src/include/postmaster/autovacuum.h
@@ -32,6 +32,7 @@ extern PGDLLIMPORT int autovacuum_max_workers;
extern PGDLLIMPORT int autovacuum_work_mem;
extern PGDLLIMPORT int autovacuum_naptime;
extern PGDLLIMPORT int autovacuum_vac_thresh;
+extern PGDLLIMPORT int autovacuum_max_thresh;
extern PGDLLIMPORT double autovacuum_vac_scale;
extern PGDLLIMPORT int autovacuum_vac_ins_thresh;
extern PGDLLIMPORT double autovacuum_vac_ins_scale;
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 8700204953..bcc6e2607b 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -309,6 +309,7 @@ typedef struct AutoVacOpts
{
bool enabled;
int vacuum_threshold;
+ int vacuum_max_threshold;
int vacuum_ins_threshold;
int analyze_threshold;
int vacuum_cost_limit;
--
2.39.3 (Apple Git-146)
