0002-Add-log_transaction-configuration-setting.patch

From b5e779771e8a7582951aff6f43a716e9e5975884 Mon Sep 17 00:00:00 2001
From: "Sergey Solovev" <sergey.soloviev@tantorlabs.ru>
Date: Thu, 4 Jul 2024 17:02:13 +0300
Subject: [PATCH] Add log_transaction configuration setting

This setting has same behaviour as log_statement - it
filter out statements that should not be logged. But
works with trasactions, that were sampled using
log_transaction_sample_rate setting.
Such feature might be helpful to avoid excessive log
messages count. At least, filter out SELECTs.
---
 doc/src/sgml/config.sgml            | 23 +++++++++++++
 src/backend/tcop/fastpath.c         |  2 +-
 src/backend/tcop/postgres.c         | 51 +++++++++++++++++++++++++----
 src/backend/utils/misc/guc_tables.c | 11 +++++++
 src/include/tcop/tcopprot.h         |  3 +-
 5 files changed, 81 insertions(+), 9 deletions(-)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 17d84bd321..41939b4e3b 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -7049,6 +7049,29 @@ local0.*    /var/log/postgresql
        </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-log-transaction" xreflabel="log_transaction">
+      <term><varname>log_transaction</varname> (<type>enum</type>)
+      <indexterm>
+       <primary><varname>log_transaction</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Controls which SQL statements in sampled transaction are logged. Transaction is
+        getting sampled according to <xref linkend="guc-log-transaction-sample-rate"/> setting.
+        Valid values are same as for <xref linkend="guc-log-statement"/>: <literal>none</literal> (off),
+        <literal>ddl</literal>, <literal>mod</literal>, and <literal>all</literal> (all statements).
+        Behaviour also similar to <xref linkend="guc-log-statement"/>.
+       </para>
+
+       <para>
+        The default is <literal>all</literal>.
+        Only superusers and users with the appropriate <literal>SET</literal>
+        privilege can change this setting.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="guc-log-startup-progress-interval" xreflabel="log_startup_progress_interval">
       <term><varname>log_startup_progress_interval</varname> (<type>integer</type>)
       <indexterm>
diff --git a/src/backend/tcop/fastpath.c b/src/backend/tcop/fastpath.c
index deac71335c..3293f75400 100644
--- a/src/backend/tcop/fastpath.c
+++ b/src/backend/tcop/fastpath.c
@@ -306,7 +306,7 @@ HandleFunctionRequest(StringInfo msgBuf)
 	/*
 	 * Emit duration logging if appropriate.
 	 */
-	switch (check_log_duration(msec_str, was_logged))
+	switch (check_log_duration(msec_str, was_logged, NIL))
 	{
 		case 1:
 			ereport(LOG,
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index e39c6804a7..7f264fa07b 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -94,6 +94,8 @@ bool		Log_disconnections = false;
 
 int			log_statement = LOGSTMT_NONE;
 
+int			log_transaction = LOGSTMT_ALL;
+
 /* GUC variable for maximum stack depth (measured in kilobytes) */
 int			max_stack_depth = 100;
 
@@ -180,6 +182,7 @@ static int	SocketBackend(StringInfo inBuf);
 static int	ReadCommand(StringInfo inBuf);
 static void forbidden_in_wal_sender(char firstchar);
 static bool check_log_statement(List *stmt_list);
+static bool	check_log_transaction_statement(List *stmt_list);
 static int	errdetail_execute(List *raw_parsetree_list);
 static int	errdetail_params(ParamListInfo params);
 static int	errdetail_abort(void);
@@ -1358,7 +1361,7 @@ exec_simple_query(const char *query_string)
 	/*
 	 * Emit duration logging if appropriate.
 	 */
-	switch (check_log_duration(msec_str, was_logged))
+	switch (check_log_duration(msec_str, was_logged, parsetree_list))
 	{
 		case 1:
 			ereport(LOG,
@@ -1594,7 +1597,7 @@ exec_parse_message(const char *query_string,	/* string to execute */
 	/*
 	 * Emit duration logging if appropriate.
 	 */
-	switch (check_log_duration(msec_str, false))
+	switch (check_log_duration(msec_str, false, NIL))
 	{
 		case 1:
 			ereport(LOG,
@@ -2048,7 +2051,7 @@ exec_bind_message(StringInfo input_message)
 	/*
 	 * Emit duration logging if appropriate.
 	 */
-	switch (check_log_duration(msec_str, false))
+	switch (check_log_duration(msec_str, false, NIL))
 	{
 		case 1:
 			ereport(LOG,
@@ -2298,7 +2301,7 @@ exec_execute_message(const char *portal_name, long max_rows)
 	/*
 	 * Emit duration logging if appropriate.
 	 */
-	switch (check_log_duration(msec_str, was_logged))
+	switch (check_log_duration(msec_str, was_logged, portal->stmts))
 	{
 		case 1:
 			ereport(LOG,
@@ -2358,6 +2361,27 @@ check_log_statement(List *stmt_list)
 	return false;
 }
 
+static bool
+check_log_transaction_statement(List *stmt_list)
+{
+	ListCell *stmt_item;
+	if (log_transaction == LOGSTMT_NONE)
+		return false;
+	if (log_transaction == LOGSTMT_ALL)
+		return true;
+
+	/* Else we have to inspect the statement(s) to see whether to log */
+	foreach (stmt_item, stmt_list)
+	{
+		Node *stmt = (Node *)lfirst(stmt_item);
+
+		if (GetCommandLogLevel(stmt) <= log_transaction)
+			return true;
+	}
+
+	return false;
+}
+
 /*
  * check_log_duration
  *		Determine whether current command's duration should be logged
@@ -2374,9 +2398,13 @@ check_log_statement(List *stmt_list)
  *
  * was_logged should be true if caller already logged query details (this
  * essentially prevents 2 from being returned).
+ *
+ * stmts can be either raw grammar output or a list of planned
+ * statements that were executed during current transaction or NIL if
+ * tag could not be determined.
  */
 int
-check_log_duration(char *msec_str, bool was_logged)
+check_log_duration(char *msec_str, bool was_logged, List *stmts)
 {
 	if (log_duration || log_min_duration_sample >= 0 ||
 		log_min_duration_statement >= 0 || xact_is_sampled)
@@ -2418,11 +2446,20 @@ check_log_duration(char *msec_str, bool was_logged)
 				(log_statement_sample_rate == 1 ||
 				 pg_prng_double(&pg_global_prng_state) <= log_statement_sample_rate);
 
-		if (exceeded_duration || in_sample || log_duration || xact_is_sampled)
+		/*
+		 * Check than current statement should be logged as transaction sampled statement according
+		 * to log_transaction paramenter. Some statements' tags could not be determined (like PARSE or BIND),
+		 * for this kinds of statements NIL passed - this is indicator to log it without paramenter check
+		 * for compatibility with old code.
+		 */
+		if (!in_sample)
+			in_sample = (stmts == NIL || check_log_transaction_statement(stmts)) && xact_is_sampled;
+
+		if (exceeded_duration || in_sample || log_duration)
 		{
 			snprintf(msec_str, 32, "%ld.%03d",
 					 secs * 1000 + msecs, usecs % 1000);
-			if ((exceeded_duration || in_sample || xact_is_sampled) && !was_logged)
+			if ((exceeded_duration || in_sample) && !was_logged)
 				return 2;
 			else
 				return 1;
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index d28b0bcb40..a6f80550cb 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -4864,6 +4864,17 @@ struct config_enum ConfigureNamesEnum[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"log_transaction", PGC_SUSET, LOGGING_WHAT,
+			gettext_noop("Sets the type of statements logged when transaction is sampled."),
+			NULL
+		},
+		&log_transaction,
+		LOGSTMT_ALL, log_statement_options,
+		NULL, NULL, NULL
+	},
+
+
 	{
 		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 643ce9cffa..a1a4474b1c 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -42,6 +42,7 @@ typedef enum
 
 extern PGDLLIMPORT bool Log_disconnections;
 extern PGDLLIMPORT int log_statement;
+extern PGDLLIMPORT int log_transaction;
 
 /* Flags for restrict_nonsystem_relation_kind value */
 #define RESTRICT_RELKIND_VIEW			0x01
@@ -82,7 +83,7 @@ extern void PostgresMain(const char *dbname,
 extern long get_stack_depth_rlimit(void);
 extern void ResetUsage(void);
 extern void ShowUsage(const char *title);
-extern int	check_log_duration(char *msec_str, bool was_logged);
+extern int	check_log_duration(char *msec_str, bool was_logged, List *stmts);
 extern void set_debug_options(int debug_flag,
 							  GucContext context, GucSource source);
 extern bool set_plan_disabling_options(const char *arg,
-- 
2.34.1