From a05d1e59324b7c88aeb52c009b4e03aaeafd2ffc Mon Sep 17 00:00:00 2001
From: Euler Taveira <euler@eulerto.com>
Date: Tue, 4 Nov 2025 17:18:20 -0300
Subject: [PATCH v10 1/2] log_min_messages per process type

Change log_min_messages from a single element to a comma-separated list
of elements. Each element is type:level. The types are archiver,
autovacuum (includes launcher and workers), backend, bgworker, bgwriter,
checkpointer, ioworker, postmaster, 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
process 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 process types. The default log level is the same (WARNING) for
all process types.
---
 doc/src/sgml/config.sgml                      |  42 ++-
 src/backend/commands/extension.c              |   2 +-
 src/backend/commands/variable.c               | 256 ++++++++++++++++++
 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         |  42 +--
 src/include/utils/guc.h                       |   5 +-
 src/include/utils/guc_hooks.h                 |   2 +
 src/test/regress/expected/guc.out             |  54 ++++
 src/test/regress/sql/guc.sql                  |  18 ++
 14 files changed, 419 insertions(+), 41 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 5560b95ee60..cbc748a3636 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -7083,7 +7083,7 @@ 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>
@@ -7092,14 +7092,38 @@ 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>type:level</literal>
+        and a single <literal>level</literal>. The list allows it to use
+        different levels per process type. Only the single <literal>level</literal>
+        is mandatory (order does not matter) and it is assigned to the process
+        types that are not specified in the list.
+        Valid process types are listed in the table below, each corresponding to
+        either postmaster, an auxiliary process type or a backend.
+        <simplelist type="vert" columns="4">
+         <member><literal>archiver</literal></member>
+         <member><literal>autovacuum</literal></member>
+         <member><literal>backend</literal></member>
+         <member><literal>bgworker</literal></member>
+         <member><literal>bgwriter</literal></member>
+         <member><literal>checkpointer</literal></member>
+         <member><literal>ioworker</literal></member>
+         <member><literal>postmaster</literal></member>
+         <member><literal>syslogger</literal></member>
+         <member><literal>slotsyncworker</literal></member>
+         <member><literal>startup</literal></member>
+         <member><literal>walreceiver</literal></member>
+         <member><literal>walsender</literal></member>
+         <member><literal>walsummarizer</literal></member>
+         <member><literal>walwriter</literal></member>
+        </simplelist>
+        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 process 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 596105ee078..688f1874f31 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -1191,7 +1191,7 @@ 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 4440aff4925..a450254d1fa 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"
@@ -41,6 +42,8 @@
 #include "utils/tzparser.h"
 #include "utils/varlena.h"
 
+static int	log_min_messages_cmp(const ListCell *a, const ListCell *b);
+
 /*
  * DATESTYLE
  */
@@ -1272,3 +1275,256 @@ check_standard_conforming_strings(bool *newval, void **extra, GucSource source)
 
 	return true;
 }
+
+/*
+ * GUC check_hook for log_min_messages
+ *
+ * The parsing consists of a comma-separated list of TYPE:LEVEL elements. TYPE
+ * is log_min_messages_process_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 process types that are not specified. For backward
+ * compatibility, the old syntax is still accepted and it means to apply the
+ * LEVEL for all process types.
+ */
+bool
+check_log_min_messages(char **newval, void **extra, GucSource source)
+{
+	char	   *rawstring;
+	List	   *elemlist;
+	StringInfoData buf;
+	char	   *result;
+	bool		first = true;
+	int			newlevel[BACKEND_NUM_TYPES];
+	bool		assigned[BACKEND_NUM_TYPES];
+	int			genericlevel = -1;	/* -1 means not assigned */
+
+	/* Initialize the array. */
+	for (int i = 0; i < BACKEND_NUM_TYPES; i++)
+	{
+		newlevel[i] = WARNING;
+		assigned[i] = false;
+	}
+
+	/* 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.");
+		list_free(elemlist);
+		guc_free(rawstring);
+		return false;
+	}
+
+	/* Validate and assign log level and process type. */
+	foreach_ptr(char, tok, elemlist)
+	{
+		char	   *sep;
+		const struct config_enum_entry *entry;
+
+		/*
+		 * Check whether there is a process 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 process 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	   *ptype;
+			bool		found = false;
+
+			ptype = guc_malloc(LOG, (sep - tok) + 1);
+			if (!ptype)
+			{
+				guc_free(rawstring);
+				list_free(elemlist);
+				return false;
+			}
+			memcpy(ptype, tok, sep - tok);
+			ptype[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(ptype);
+				guc_free(rawstring);
+				list_free(elemlist);
+				return false;
+			}
+
+			/*
+			 * Is the process type name valid? There might be multiple entries
+			 * per process 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_process_types[i], ptype) == 0)
+				{
+					/* Reject duplicates for a process type. */
+					if (assigned[i])
+					{
+						GUC_check_errdetail("Process type \"%s\" was already assigned.", ptype);
+						guc_free(ptype);
+						guc_free(rawstring);
+						list_free(elemlist);
+						return false;
+					}
+
+					newlevel[i] = entry->val;
+					assigned[i] = true;
+					found = true;
+				}
+			}
+
+			if (!found)
+			{
+				GUC_check_errdetail("Unrecognized process type: \"%s\".", ptype);
+				guc_free(ptype);
+				guc_free(rawstring);
+				list_free(elemlist);
+				return false;
+			}
+
+			guc_free(ptype);
+		}
+	}
+
+	/*
+	 * 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 process types
+	 * 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;
+	}
+
+	/*
+	 * Use a stable representation of log_min_messages. The generic level is
+	 * always the first element and the other elements (type:level) are sorted
+	 * by process type. See log_min_messages_cmp for details.
+	 */
+	list_sort(elemlist, log_min_messages_cmp);
+
+	initStringInfo(&buf);
+	foreach_ptr(char, tok, elemlist)
+	{
+		if (first)
+		{
+			appendStringInfoString(&buf, tok);
+			first = false;
+		}
+		else
+		{
+			appendStringInfo(&buf, ", %s", tok);
+		}
+	}
+
+	result = (char *) guc_malloc(LOG, buf.len + 1);
+	if (!result)
+		return false;
+	memcpy(result, buf.data, buf.len);
+	result[buf.len] = '\0';
+
+	guc_free(*newval);
+	*newval = result;
+
+	guc_free(rawstring);
+	list_free(elemlist);
+	pfree(buf.data);
+
+	/*
+	 * 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;
+}
+
+static int
+log_min_messages_cmp(const ListCell *a, const ListCell *b)
+{
+	const char *s = lfirst(a);
+	const char *t = lfirst(b);
+
+	if (strchr(s, ':') == NULL)
+		return -1;
+	else if (strchr(t, ':') == NULL)
+		return 1;
+	else
+		return strcmp(s, t);
+}
+
+/*
+ * 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 926fd6f2700..08553c0f024 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -178,7 +178,7 @@ 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 e6a4ef99059..4e9143b6e6f 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 563f20374ff..efba20fa8b9 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 f0260e6e412..3297c4bc30c 100644
--- a/src/backend/utils/misc/guc_parameters.dat
+++ b/src/backend/utils/misc/guc_parameters.dat
@@ -1686,12 +1686,14 @@
   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 13c569d8790..0aebb9c8e24 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 standard_conforming_strings = true;
 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
@@ -647,6 +647,23 @@ 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_process_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 c4f92fcdac8..ad0804ccb9f 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 type: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 0b99eaabfd0..0ddd805f0e7 100644
--- a/src/include/postmaster/proctypelist.h
+++ b/src/include/postmaster/proctypelist.h
@@ -25,27 +25,27 @@
  */
 
 /*
- * List of process types (symbol, description, Main function, shmem_attach)
- * entries.
+ * List of process types (symbol, category, description, Main function,
+ * shmem_attach, message level) entries.
  */
 
 
-/* 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, "postmaster", 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 bf39878c43e..8acbdba7ff5 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 +329,8 @@ extern PGDLLIMPORT bool trace_sort;
 extern PGDLLIMPORT bool optimize_bounded_sort;
 #endif
 
+extern PGDLLIMPORT const char *const log_min_messages_process_types[];
+
 /*
  * Declarations for options for enum values
  *
@@ -344,6 +346,7 @@ 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 b6ecb0e769f..9c90670d9b8 100644
--- a/src/include/utils/guc_hooks.h
+++ b/src/include/utils/guc_hooks.h
@@ -177,5 +177,7 @@ 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..9a6fd503009 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:  Process 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 process 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                                         
+-------------------------------------------------------------------------------------------------
+ fatal, archiver:debug2, autovacuum:debug1, backend:error, checkpointer:debug3, 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      
+----------------------------
+ warning, autovacuum:debug1
+(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;
-- 
2.47.3

