On Sun, Oct 5, 2025, at 11:18 AM, Euler Taveira wrote:
> This new patch contains the following changes:
>
> - patch was rebased
> - use commit dbf8cfb4f02
> - use some GUC memory allocation functions
> - avoid one memory allocation (suggested by Japin Li)
> - rename backend type: logger -> syslogger
> - adjust tests to increase test coverage
> - improve documentation and comments to reflect the current state
>
Patch was rebased since commit fce7c73fba4 broke it. No modifications.
--
Euler Taveira
EDB https://www.enterprisedb.com/
From e457cc99c20f54d8e7e998104402e849ecf83c14 Mon Sep 17 00:00:00 2001
From: Euler Taveira <[email protected]>
Date: Tue, 4 Nov 2025 17:18:20 -0300
Subject: [PATCH v5] log_min_messages per backend type
Change log_min_messages from a single element to a comma-separated list
of elements. Each element is backendtype:loglevel. The backendtype are
archiver, autovacuum (includes launcher and workers), backend, bgworker,
bgwriter, checkpointer, ioworker, syslogger, slotsyncworker, startup,
walreceiver, walsender, walsummarizer and walwriter. A single log level
should be part of this list and it is applied as a final step to the
backend types that were not informed.
The old syntax (a single log level) is still accepted for backward
compatibility. In this case, it means the informed log level is applied
for all backend types. The default log level is the same (WARNING) for
all backend types.
---
doc/src/sgml/config.sgml | 31 ++-
src/backend/commands/extension.c | 2 +-
src/backend/commands/variable.c | 205 ++++++++++++++++++
src/backend/postmaster/launch_backend.c | 2 +-
src/backend/utils/error/elog.c | 2 +-
src/backend/utils/init/miscinit.c | 2 +-
src/backend/utils/misc/guc_parameters.dat | 10 +-
src/backend/utils/misc/guc_tables.c | 21 +-
src/backend/utils/misc/postgresql.conf.sample | 2 +
src/include/postmaster/proctypelist.h | 38 ++--
src/include/utils/guc.h | 6 +-
src/include/utils/guc_hooks.h | 2 +
src/test/regress/expected/guc.out | 54 +++++
src/test/regress/sql/guc.sql | 18 ++
14 files changed, 356 insertions(+), 39 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d8a9f14b618..2ac1e65aa60 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -7053,7 +7053,7 @@ local0.* /var/log/postgresql
<variablelist>
<varlistentry id="guc-log-min-messages" xreflabel="log_min_messages">
- <term><varname>log_min_messages</varname> (<type>enum</type>)
+ <term><varname>log_min_messages</varname> (<type>string</type>)
<indexterm>
<primary><varname>log_min_messages</varname> configuration parameter</primary>
</indexterm>
@@ -7062,14 +7062,27 @@ local0.* /var/log/postgresql
<para>
Controls which <link linkend="runtime-config-severity-levels">message
levels</link> are written to the server log.
- Valid values are <literal>DEBUG5</literal>, <literal>DEBUG4</literal>,
- <literal>DEBUG3</literal>, <literal>DEBUG2</literal>, <literal>DEBUG1</literal>,
- <literal>INFO</literal>, <literal>NOTICE</literal>, <literal>WARNING</literal>,
- <literal>ERROR</literal>, <literal>LOG</literal>, <literal>FATAL</literal>, and
- <literal>PANIC</literal>. Each level includes all the levels that
- follow it. The later the level, the fewer messages are sent
- to the log. The default is <literal>WARNING</literal>. Note that
- <literal>LOG</literal> has a different rank here than in
+ Valid values are a comma-separated list of <literal>backendtype:level</literal>
+ and a single <literal>level</literal>. The list allows it to use
+ different levels per backend type. Only the single <literal>level</literal>
+ is mandatory (order does not matter) and it is assigned to the backend
+ types that are not specified in the list.
+ Valid <literal>backendtype</literal> values are <literal>archiver</literal>,
+ <literal>autovacuum</literal>, <literal>backend</literal>,
+ <literal>bgworker</literal>, <literal>bgwriter</literal>,
+ <literal>checkpointer</literal>, <literal>ioworker</literal>,
+ <literal>syslogger</literal>, <literal>slotsyncworker</literal>,
+ <literal>startup</literal>, <literal>walreceiver</literal>,
+ <literal>walsender</literal>, <literal>walsummarizer</literal>, and
+ <literal>walwriter</literal>.
+ Valid <literal>level</literal> values are <literal>DEBUG5</literal>,
+ <literal>DEBUG4</literal>, <literal>DEBUG3</literal>, <literal>DEBUG2</literal>,
+ <literal>DEBUG1</literal>, <literal>INFO</literal>, <literal>NOTICE</literal>,
+ <literal>WARNING</literal>, <literal>ERROR</literal>, <literal>LOG</literal>,
+ <literal>FATAL</literal>, and <literal>PANIC</literal>. Each level includes
+ all the levels that follow it. The later the level, the fewer messages are sent
+ to the log. The default is <literal>WARNING</literal> for all backend types.
+ Note that <literal>LOG</literal> has a different rank here than in
<xref linkend="guc-client-min-messages"/>.
Only superusers and users with the appropriate <literal>SET</literal>
privilege can change this setting.
diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index 93ef1ad106f..81f7bc5e567 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -1143,7 +1143,7 @@ execute_extension_script(Oid extensionOid, ExtensionControlFile *control,
(void) set_config_option("client_min_messages", "warning",
PGC_USERSET, PGC_S_SESSION,
GUC_ACTION_SAVE, true, 0, false);
- if (log_min_messages < WARNING)
+ if (log_min_messages[MyBackendType] < WARNING)
(void) set_config_option_ext("log_min_messages", "warning",
PGC_SUSET, PGC_S_SESSION,
BOOTSTRAP_SUPERUSERID,
diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c
index 608f10d9412..c86bdf74f41 100644
--- a/src/backend/commands/variable.c
+++ b/src/backend/commands/variable.c
@@ -34,6 +34,7 @@
#include "utils/backend_status.h"
#include "utils/datetime.h"
#include "utils/fmgrprotos.h"
+#include "utils/guc.h"
#include "utils/guc_hooks.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
@@ -1257,3 +1258,207 @@ check_ssl(bool *newval, void **extra, GucSource source)
#endif
return true;
}
+
+/*
+ * GUC check_hook for log_min_messages
+ *
+ * The parsing consists of a comma-separated list of BACKENDTYPENAME:LEVEL
+ * elements. BACKENDTYPENAME is log_min_messages_backend_types. LEVEL is
+ * server_message_level_options. A single LEVEL element should be part of this
+ * list and it is applied as a final step to the backend types that are not
+ * specified. For backward compatibility, the old syntax is still accepted and
+ * it means to apply the LEVEL for all backend types.
+ */
+bool
+check_log_min_messages(char **newval, void **extra, GucSource source)
+{
+ char *rawstring;
+ List *elemlist;
+ ListCell *l;
+ int newlevel[BACKEND_NUM_TYPES];
+ bool assigned[BACKEND_NUM_TYPES];
+ int genericlevel = -1; /* -1 means not assigned */
+
+ /* Initialize the array. */
+ memset(newlevel, WARNING, BACKEND_NUM_TYPES * sizeof(int));
+ memset(assigned, false, BACKEND_NUM_TYPES * sizeof(bool));
+
+ /* Need a modifiable copy of string. */
+ rawstring = guc_strdup(LOG, *newval);
+
+ /* Parse string into list of identifiers. */
+ if (!SplitGUCList(rawstring, ',', &elemlist))
+ {
+ /* syntax error in list */
+ GUC_check_errdetail("List syntax is invalid.");
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+
+ /* Validate and assign log level and backend type. */
+ foreach(l, elemlist)
+ {
+ char *tok = (char *) lfirst(l);
+ char *sep;
+ const struct config_enum_entry *entry;
+
+ /*
+ * Check whether there is a backend type following the log level. If
+ * there is no separator, it means this is the generic log level. The
+ * generic log level will be assigned to the backend types that were
+ * not informed.
+ */
+ sep = strchr(tok, ':');
+ if (sep == NULL)
+ {
+ bool found = false;
+
+ /* Reject duplicates for generic log level. */
+ if (genericlevel != -1)
+ {
+ GUC_check_errdetail("Generic log level was already assigned.");
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+
+ /* Is the log level valid? */
+ for (entry = server_message_level_options; entry && entry->name; entry++)
+ {
+ if (pg_strcasecmp(entry->name, tok) == 0)
+ {
+ genericlevel = entry->val;
+ found = true;
+ break;
+ }
+ }
+
+ if (!found)
+ {
+ GUC_check_errdetail("Unrecognized log level: \"%s\".", tok);
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+ }
+ else
+ {
+ char *loglevel;
+ char *btype;
+ bool found = false;
+
+ btype = guc_malloc(LOG, (sep - tok) + 1);
+ if (!btype)
+ {
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+ memcpy(btype, tok, sep - tok);
+ btype[sep - tok] = '\0';
+ loglevel = sep + 1;
+
+ /* Is the log level valid? */
+ for (entry = server_message_level_options; entry && entry->name; entry++)
+ {
+ if (pg_strcasecmp(entry->name, loglevel) == 0)
+ {
+ found = true;
+ break;
+ }
+ }
+
+ if (!found)
+ {
+ GUC_check_errdetail("Unrecognized log level: \"%s\".", loglevel);
+ guc_free(btype);
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+
+ /*
+ * Is the backend type name valid? There might be multiple entries
+ * per backend type, don't bail out because it can assign the
+ * value for multiple entries.
+ */
+ found = false;
+ for (int i = 0; i < BACKEND_NUM_TYPES; i++)
+ {
+ if (pg_strcasecmp(log_min_messages_backend_types[i], btype) == 0)
+ {
+ /* Reject duplicates for a backend type. */
+ if (assigned[i])
+ {
+ GUC_check_errdetail("Backend type \"%s\" was already assigned.", btype);
+ guc_free(btype);
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+
+ newlevel[i] = entry->val;
+ assigned[i] = true;
+ found = true;
+ }
+ }
+
+ if (!found)
+ {
+ GUC_check_errdetail("Unrecognized backend type: \"%s\".", btype);
+ guc_free(btype);
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+
+ guc_free(btype);
+ }
+ }
+
+ /*
+ * The generic log level must be specified. It is the fallback value.
+ */
+ if (genericlevel == -1)
+ {
+ GUC_check_errdetail("Generic log level was not defined.");
+ guc_free(rawstring);
+ list_free(elemlist);
+ return false;
+ }
+
+ /*
+ * Apply the generic log level after all of the specific backend type have
+ * been assigned. Hence, it doesn't matter the order you specify the
+ * generic log level, the final result will be the same.
+ */
+ for (int i = 0; i < BACKEND_NUM_TYPES; i++)
+ {
+ if (!assigned[i])
+ newlevel[i] = genericlevel;
+ }
+
+ guc_free(rawstring);
+ list_free(elemlist);
+
+ /*
+ * Pass back data for assign_log_min_messages to use.
+ */
+ *extra = guc_malloc(LOG, BACKEND_NUM_TYPES * sizeof(int));
+ if (!*extra)
+ return false;
+ memcpy(*extra, newlevel, BACKEND_NUM_TYPES * sizeof(int));
+
+ return true;
+}
+
+/*
+ * GUC assign_hook for log_min_messages
+ */
+void
+assign_log_min_messages(const char *newval, void *extra)
+{
+ for (int i = 0; i < BACKEND_NUM_TYPES; i++)
+ log_min_messages[i] = ((int *) extra)[i];
+}
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 976638a58ac..c2a044321d1 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -179,7 +179,7 @@ typedef struct
} child_process_kind;
static child_process_kind child_process_kinds[] = {
-#define PG_PROCTYPE(bktype, description, main_func, shmem_attach) \
+#define PG_PROCTYPE(bktype, bkcategory, description, main_func, shmem_attach, log_min_messages) \
[bktype] = {description, main_func, shmem_attach},
#include "postmaster/proctypelist.h"
#undef PG_PROCTYPE
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 29643c51439..15d771a16c9 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -235,7 +235,7 @@ is_log_level_output(int elevel, int log_min_level)
static inline bool
should_output_to_server(int elevel)
{
- return is_log_level_output(elevel, log_min_messages);
+ return is_log_level_output(elevel, log_min_messages[MyBackendType]);
}
/*
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index fec79992c8d..2c3926cbadf 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -266,7 +266,7 @@ GetBackendTypeDesc(BackendType backendType)
switch (backendType)
{
-#define PG_PROCTYPE(bktype, description, main_func, shmem_attach) \
+#define PG_PROCTYPE(bktype, bkcategory, description, main_func, shmem_attach, log_min_messages) \
case bktype: backendDesc = description; break;
#include "postmaster/proctypelist.h"
#undef PG_PROCTYPE
diff --git a/src/backend/utils/misc/guc_parameters.dat b/src/backend/utils/misc/guc_parameters.dat
index 1128167c025..55dfc2e6548 100644
--- a/src/backend/utils/misc/guc_parameters.dat
+++ b/src/backend/utils/misc/guc_parameters.dat
@@ -1676,12 +1676,14 @@
options => 'server_message_level_options',
},
-{ name => 'log_min_messages', type => 'enum', context => 'PGC_SUSET', group => 'LOGGING_WHEN',
+{ name => 'log_min_messages', type => 'string', context => 'PGC_SUSET', group => 'LOGGING_WHEN',
short_desc => 'Sets the message levels that are logged.',
long_desc => 'Each level includes all the levels that follow it. The later the level, the fewer messages are sent.',
- variable => 'log_min_messages',
- boot_val => 'WARNING',
- options => 'server_message_level_options',
+ flags => 'GUC_LIST_INPUT',
+ variable => 'log_min_messages_string',
+ boot_val => '"WARNING"',
+ check_hook => 'check_log_min_messages',
+ assign_hook => 'assign_log_min_messages',
},
{ name => 'log_parameter_max_length', type => 'int', context => 'PGC_SUSET', group => 'LOGGING_WHAT',
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 0209b2067a2..8761b371de7 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -146,7 +146,7 @@ static const struct config_enum_entry client_message_level_options[] = {
{NULL, 0, false}
};
-static const struct config_enum_entry server_message_level_options[] = {
+const struct config_enum_entry server_message_level_options[] = {
{"debug5", DEBUG5, false},
{"debug4", DEBUG4, false},
{"debug3", DEBUG3, false},
@@ -537,7 +537,6 @@ static bool default_with_oids = false;
bool current_role_is_superuser;
int log_min_error_statement = ERROR;
-int log_min_messages = WARNING;
int client_min_messages = NOTICE;
int log_min_duration_sample = -1;
int log_min_duration_statement = -1;
@@ -595,6 +594,7 @@ static char *server_version_string;
static int server_version_num;
static char *debug_io_direct_string;
static char *restrict_nonsystem_relation_kind_string;
+static char *log_min_messages_string;
#ifdef HAVE_SYSLOG
#define DEFAULT_SYSLOG_FACILITY LOG_LOCAL0
@@ -639,6 +639,23 @@ char *role_string;
/* should be static, but guc.c needs to get at this */
bool in_hot_standby_guc;
+/*
+ * log_min_messages
+ */
+int log_min_messages[] = {
+#define PG_PROCTYPE(bktype, bkcategory, description, main_func, shmem_attach, log_min_messages) \
+ [bktype] = log_min_messages,
+#include "postmaster/proctypelist.h"
+#undef PG_PROCTYPE
+};
+
+const char *const log_min_messages_backend_types[] = {
+#define PG_PROCTYPE(bktype, bkcategory, description, main_func, shmem_attach, log_min_messages) \
+ [bktype] = bkcategory,
+#include "postmaster/proctypelist.h"
+#undef PG_PROCTYPE
+};
+
/*
* Displayable names for context types (enum GucContext)
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index f62b61967ef..fde1054ae0f 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -541,6 +541,8 @@
# log
# fatal
# panic
+ # and an optional comma-separated list
+ # of backendtype:level
#log_min_error_statement = error # values in order of decreasing detail:
# debug5
diff --git a/src/include/postmaster/proctypelist.h b/src/include/postmaster/proctypelist.h
index 242862451d8..f18e3342285 100644
--- a/src/include/postmaster/proctypelist.h
+++ b/src/include/postmaster/proctypelist.h
@@ -30,22 +30,22 @@
*/
-/* bktype, description, main_func, shmem_attach */
-PG_PROCTYPE(B_ARCHIVER, gettext_noop("archiver"), PgArchiverMain, true)
-PG_PROCTYPE(B_AUTOVAC_LAUNCHER, gettext_noop("autovacuum launcher"), AutoVacLauncherMain, true)
-PG_PROCTYPE(B_AUTOVAC_WORKER, gettext_noop("autovacuum worker"), AutoVacWorkerMain, true)
-PG_PROCTYPE(B_BACKEND, gettext_noop("client backend"), BackendMain, true)
-PG_PROCTYPE(B_BG_WORKER, gettext_noop("background worker"), BackgroundWorkerMain, true)
-PG_PROCTYPE(B_BG_WRITER, gettext_noop("background writer"), BackgroundWriterMain, true)
-PG_PROCTYPE(B_CHECKPOINTER, gettext_noop("checkpointer"), CheckpointerMain, true)
-PG_PROCTYPE(B_DEAD_END_BACKEND, gettext_noop("dead-end client backend"), BackendMain, true)
-PG_PROCTYPE(B_INVALID, gettext_noop("unrecognized"), NULL, false)
-PG_PROCTYPE(B_IO_WORKER, gettext_noop("io worker"), IoWorkerMain, true)
-PG_PROCTYPE(B_LOGGER, gettext_noop("syslogger"), SysLoggerMain, false)
-PG_PROCTYPE(B_SLOTSYNC_WORKER, gettext_noop("slotsync worker"), ReplSlotSyncWorkerMain, true)
-PG_PROCTYPE(B_STANDALONE_BACKEND, gettext_noop("standalone backend"), NULL, false)
-PG_PROCTYPE(B_STARTUP, gettext_noop("startup"), StartupProcessMain, true)
-PG_PROCTYPE(B_WAL_RECEIVER, gettext_noop("walreceiver"), WalReceiverMain, true)
-PG_PROCTYPE(B_WAL_SENDER, gettext_noop("walsender"), NULL, true)
-PG_PROCTYPE(B_WAL_SUMMARIZER, gettext_noop("walsummarizer"), WalSummarizerMain, true)
-PG_PROCTYPE(B_WAL_WRITER, gettext_noop("walwriter"), WalWriterMain, true)
+/* bktype, bkcategory, description, main_func, shmem_attach, log_min_messages */
+PG_PROCTYPE(B_ARCHIVER, "archiver", gettext_noop("archiver"), PgArchiverMain, true, WARNING)
+PG_PROCTYPE(B_AUTOVAC_LAUNCHER, "autovacuum", gettext_noop("autovacuum launcher"), AutoVacLauncherMain, true, WARNING)
+PG_PROCTYPE(B_AUTOVAC_WORKER, "autovacuum", gettext_noop("autovacuum worker"), AutoVacWorkerMain, true, WARNING)
+PG_PROCTYPE(B_BACKEND, "backend", gettext_noop("client backend"), BackendMain, true, WARNING)
+PG_PROCTYPE(B_BG_WORKER, "bgworker", gettext_noop("background worker"), BackgroundWorkerMain, true, WARNING)
+PG_PROCTYPE(B_BG_WRITER, "bgwriter", gettext_noop("background writer"), BackgroundWriterMain, true, WARNING)
+PG_PROCTYPE(B_CHECKPOINTER, "checkpointer", gettext_noop("checkpointer"), CheckpointerMain, true, WARNING)
+PG_PROCTYPE(B_DEAD_END_BACKEND, "backend", gettext_noop("dead-end client backend"), BackendMain, true, WARNING)
+PG_PROCTYPE(B_INVALID, "backend", gettext_noop("unrecognized"), NULL, false, WARNING)
+PG_PROCTYPE(B_IO_WORKER, "ioworker", gettext_noop("io worker"), IoWorkerMain, true, WARNING)
+PG_PROCTYPE(B_LOGGER, "syslogger", gettext_noop("syslogger"), SysLoggerMain, false, WARNING)
+PG_PROCTYPE(B_SLOTSYNC_WORKER, "slotsyncworker", gettext_noop("slotsync worker"), ReplSlotSyncWorkerMain, true, WARNING)
+PG_PROCTYPE(B_STANDALONE_BACKEND, "backend", gettext_noop("standalone backend"), NULL, false, WARNING)
+PG_PROCTYPE(B_STARTUP, "startup", gettext_noop("startup"), StartupProcessMain, true, WARNING)
+PG_PROCTYPE(B_WAL_RECEIVER, "walreceiver", gettext_noop("walreceiver"), WalReceiverMain, true, WARNING)
+PG_PROCTYPE(B_WAL_SENDER, "walsender", gettext_noop("walsender"), NULL, true, WARNING)
+PG_PROCTYPE(B_WAL_SUMMARIZER, "walsummarizer", gettext_noop("walsummarizer"), WalSummarizerMain, true, WARNING)
+PG_PROCTYPE(B_WAL_WRITER, "walwriter", gettext_noop("walwriter"), WalWriterMain, true, WARNING)
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index f21ec37da89..a4e52433ac0 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -295,7 +295,7 @@ extern PGDLLIMPORT bool log_duration;
extern PGDLLIMPORT int log_parameter_max_length;
extern PGDLLIMPORT int log_parameter_max_length_on_error;
extern PGDLLIMPORT int log_min_error_statement;
-extern PGDLLIMPORT int log_min_messages;
+extern PGDLLIMPORT int log_min_messages[];
extern PGDLLIMPORT int client_min_messages;
extern PGDLLIMPORT int log_min_duration_sample;
extern PGDLLIMPORT int log_min_duration_statement;
@@ -329,6 +329,9 @@ extern PGDLLIMPORT bool trace_sort;
extern PGDLLIMPORT bool optimize_bounded_sort;
#endif
+/* log_min_messages */
+extern PGDLLIMPORT const char *const log_min_messages_backend_types[];
+
/*
* Declarations for options for enum values
*
@@ -344,6 +347,7 @@ extern PGDLLIMPORT const struct config_enum_entry archive_mode_options[];
extern PGDLLIMPORT const struct config_enum_entry dynamic_shared_memory_options[];
extern PGDLLIMPORT const struct config_enum_entry io_method_options[];
extern PGDLLIMPORT const struct config_enum_entry recovery_target_action_options[];
+extern PGDLLIMPORT const struct config_enum_entry server_message_level_options[];
extern PGDLLIMPORT const struct config_enum_entry wal_level_options[];
extern PGDLLIMPORT const struct config_enum_entry wal_sync_method_options[];
diff --git a/src/include/utils/guc_hooks.h b/src/include/utils/guc_hooks.h
index 82ac8646a8d..e6ffc96468f 100644
--- a/src/include/utils/guc_hooks.h
+++ b/src/include/utils/guc_hooks.h
@@ -174,5 +174,7 @@ extern void assign_wal_sync_method(int new_wal_sync_method, void *extra);
extern bool check_synchronized_standby_slots(char **newval, void **extra,
GucSource source);
extern void assign_synchronized_standby_slots(const char *newval, void *extra);
+extern bool check_log_min_messages(char **newval, void **extra, GucSource source);
+extern void assign_log_min_messages(const char *newval, void *extra);
#endif /* GUC_HOOKS_H */
diff --git a/src/test/regress/expected/guc.out b/src/test/regress/expected/guc.out
index d6fb879f500..f6ebd27b1a9 100644
--- a/src/test/regress/expected/guc.out
+++ b/src/test/regress/expected/guc.out
@@ -935,3 +935,57 @@ SELECT name FROM tab_settings_flags
(0 rows)
DROP TABLE tab_settings_flags;
+-- Test log_min_messages
+SET log_min_messages TO foo; -- fail
+ERROR: invalid value for parameter "log_min_messages": "foo"
+DETAIL: Unrecognized log level: "foo".
+SET log_min_messages TO fatal;
+SHOW log_min_messages;
+ log_min_messages
+------------------
+ fatal
+(1 row)
+
+SET log_min_messages TO 'fatal';
+SHOW log_min_messages;
+ log_min_messages
+------------------
+ fatal
+(1 row)
+
+SET log_min_messages TO 'checkpointer:debug2, autovacuum:debug1'; --fail
+ERROR: invalid value for parameter "log_min_messages": "checkpointer:debug2, autovacuum:debug1"
+DETAIL: Generic log level was not defined.
+SET log_min_messages TO 'debug1, backend:error, fatal'; -- fail
+ERROR: invalid value for parameter "log_min_messages": "debug1, backend:error, fatal"
+DETAIL: Generic log level was already assigned.
+SET log_min_messages TO 'backend:error, debug1, backend:warning'; -- fail
+ERROR: invalid value for parameter "log_min_messages": "backend:error, debug1, backend:warning"
+DETAIL: Backend type "backend" was already assigned.
+SET log_min_messages TO 'backend:error, foo:fatal, archiver:debug1'; -- fail
+ERROR: invalid value for parameter "log_min_messages": "backend:error, foo:fatal, archiver:debug1"
+DETAIL: Unrecognized backend type: "foo".
+SET log_min_messages TO 'backend:error, checkpointer:bar, archiver:debug1'; -- fail
+ERROR: invalid value for parameter "log_min_messages": "backend:error, checkpointer:bar, archiver:debug1"
+DETAIL: Unrecognized log level: "bar".
+SET log_min_messages TO 'backend:error, checkpointer:debug3, fatal, archiver:debug2, autovacuum:debug1, walsender:debug3';
+SHOW log_min_messages;
+ log_min_messages
+-------------------------------------------------------------------------------------------------
+ backend:error, checkpointer:debug3, fatal, archiver:debug2, autovacuum:debug1, walsender:debug3
+(1 row)
+
+SET log_min_messages TO 'warning, autovacuum:debug1';
+SHOW log_min_messages;
+ log_min_messages
+----------------------------
+ warning, autovacuum:debug1
+(1 row)
+
+SET log_min_messages TO 'autovacuum:debug1, warning';
+SHOW log_min_messages;
+ log_min_messages
+----------------------------
+ autovacuum:debug1, warning
+(1 row)
+
diff --git a/src/test/regress/sql/guc.sql b/src/test/regress/sql/guc.sql
index bafaf067e82..f7dfc909b42 100644
--- a/src/test/regress/sql/guc.sql
+++ b/src/test/regress/sql/guc.sql
@@ -377,3 +377,21 @@ SELECT name FROM tab_settings_flags
WHERE no_reset AND NOT no_reset_all
ORDER BY 1;
DROP TABLE tab_settings_flags;
+
+-- Test log_min_messages
+SET log_min_messages TO foo; -- fail
+SET log_min_messages TO fatal;
+SHOW log_min_messages;
+SET log_min_messages TO 'fatal';
+SHOW log_min_messages;
+SET log_min_messages TO 'checkpointer:debug2, autovacuum:debug1'; --fail
+SET log_min_messages TO 'debug1, backend:error, fatal'; -- fail
+SET log_min_messages TO 'backend:error, debug1, backend:warning'; -- fail
+SET log_min_messages TO 'backend:error, foo:fatal, archiver:debug1'; -- fail
+SET log_min_messages TO 'backend:error, checkpointer:bar, archiver:debug1'; -- fail
+SET log_min_messages TO 'backend:error, checkpointer:debug3, fatal, archiver:debug2, autovacuum:debug1, walsender:debug3';
+SHOW log_min_messages;
+SET log_min_messages TO 'warning, autovacuum:debug1';
+SHOW log_min_messages;
+SET log_min_messages TO 'autovacuum:debug1, warning';
+SHOW log_min_messages;
--
2.39.5
