[CF 4735] v12 - Support a wildcard in backtrace_functions

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https://commitfest.postgresql.org/patch/4735

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Patch(es): https://www.postgresql.org/message-id/CAGECzQThxK+ZNLNasmiMXXN_TfUJEVDC49pZ2LB_aSvjW2tigA@mail.gmail.com
Author(s): Jelte Fennema-Nio

Author: Commitfest Bot

doc/src/sgml/config.sgml

@@ -7435,6 +7435,44 @@ local0.*    /var/log/postgresql
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-log-backtrace-mode" xreflabel="log_backtrace_mode">
+      <term><varname>log_backtrace_mode</varname> (<type>boolean</type>)
+      <indexterm>
+        <primary><varname>log_backtrace_mode</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        If this parameter is set to <literal>all</literal> then for all log
+        entries a backtrace is written to the server log together with the log
+        message. If this parameter is set to <literal>internal_error</literal> then
+        such a backtrace is only written for logs with error code XX000
+        (internal error; see also <xref linkend="errcodes-appendix"/>).
+        This can be used to debug such internal errors (which should normally
+        not happen in production). Finally, if this parameter is set to
+        <literal>none</literal> (the default), no backtraces are ever written
+        to the server log.
+       </para>
+
+       <para>
+        The logs for which a backtrace is written can be further restricted
+        using <xref linkend="guc-backtrace-min-level"/> (default:
+        <literal>ERROR</literal>) and <xref linkend="guc-backtrace-functions"/>
+        (default: empty string, meaning all).
+       </para>
+
+       <para>
+        Backtrace support is not available on all platforms, and the quality
+        of the backtraces depends on compilation options.
+       </para>
+
+       <para>
+        Only superusers and users with the appropriate <literal>SET</literal>
+        privilege can change this setting.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="guc-log-checkpoints" xreflabel="log_checkpoints">
       <term><varname>log_checkpoints</varname> (<type>boolean</type>)
       <indexterm>
@@ -12088,16 +12126,45 @@ dynamic_library_path = '/usr/local/lib/postgresql:$libdir'
       </term>
       <listitem>
        <para>
-        This parameter contains a comma-separated list of C function names.
-        If an error is raised and the name of the internal C function where
-        the error happens matches a value in the list, then a backtrace is
-        written to the server log together with the error message.  This can
-        be used to debug specific areas of the source code.
+        This parameter can contain a comma-separated list of C function names,
+        which can be used to filter for which logs a backtrace is written to
+        the server log.
+        If a log entry is raised and the name of the
+        internal C function where the error happens does not match any of the
+        values in the list, then no backtrace is written to the server log.
+        This can be used to only debug specific areas of the source code.
        </para>
 
        <para>
-        Backtrace support is not available on all platforms, and the quality
-        of the backtraces depends on compilation options.
+        The empty string (the default) disables any such filtering. So for any
+        logs that match both <xref linkend="guc-log-backtrace-mode"/> and
+        <xref linkend="guc-backtrace-min-level"/> a backtrace is
+        written to the server log.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry id="guc-backtrace-min-level" xreflabel="backtrace_min_level">
+      <term><varname>backtrace_min_level</varname> (<type>string</type>)
+      <indexterm>
+        <primary><varname>backtrace_min_level</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Controls which <link linkend="runtime-config-severity-levels">message
+        levels</link> cause backtraces to be written to the log, for log
+        messages that match both <xref linkend="guc-log-backtrace-mode"/> and
+        <xref linkend="guc-backtrace-functions"/>.
+        Valid values are <literal>DEBUG5</literal>, <literal>DEBUG4</literal>,
+        <literal>DEBUG3</literal>, <literal>DEBUG2</literal>, <literal>DEBUG1</literal>,
+        <literal>LOG</literal>, <literal>INFO</literal>, <literal>NOTICE</literal>,
+        <literal>WARNING</literal>, <literal>ERROR</literal>, <literal>FATAL</literal>,
+        and <literal>PANIC</literal>.  Each level includes all the levels that
+        follow it.  The later the level, the fewer messages result in a
+        backtrace.  The default is <literal>ERROR</literal>.  Note that
+        <literal>LOG</literal> has a different rank here than in
+        <xref linkend="guc-log-min-messages"/>.
        </para>
 
        <para>
@@ -12130,6 +12197,7 @@ dynamic_library_path = '/usr/local/lib/postgresql:$libdir'
       </listitem>
      </varlistentry>
 
+
      <varlistentry id="guc-debug-discard-caches" xreflabel="debug_discard_caches">
       <term><varname>debug_discard_caches</varname> (<type>integer</type>)
       <indexterm>

src/backend/utils/error/elog.c

@@ -110,6 +110,7 @@ int			Log_error_verbosity = PGERROR_DEFAULT;
 char	   *Log_line_prefix = NULL; /* format for extra log line info */
 int			Log_destination = LOG_DESTINATION_STDERR;
 char	   *Log_destination_string = NULL;
+int			log_backtrace = LOGBACKTRACE_NONE;
 bool		syslog_sequence_numbers = true;
 bool		syslog_split_messages = true;
 
@@ -178,6 +179,7 @@ static void set_stack_entry_domain(ErrorData *edata, const char *domain);
 static void set_stack_entry_location(ErrorData *edata,
 									 const char *filename, int lineno,
 									 const char *funcname);
+static bool matches_backtrace_gucs(ErrorData *edata);
 static bool matches_backtrace_functions(const char *funcname);
 static pg_noinline void set_backtrace(ErrorData *edata, int num_skip);
 static void set_errdata_field(MemoryContextData *cxt, char **ptr, const char *str);
@@ -493,10 +495,7 @@ errfinish(const char *filename, int lineno, const char *funcname)
 	oldcontext = MemoryContextSwitchTo(ErrorContext);
 
 	/* Collect backtrace, if enabled and we didn't already */
-	if (!edata->backtrace &&
-		edata->funcname &&
-		backtrace_functions &&
-		matches_backtrace_functions(edata->funcname))
+	if (!edata->backtrace && matches_backtrace_gucs(edata))
 		set_backtrace(edata, 2);
 
 	/*
@@ -816,6 +815,26 @@ set_stack_entry_location(ErrorData *edata,
 	edata->funcname = funcname;
 }
 
+/*
+ * matches_backtrace_gucs --- checks whether the log entry matches
+ * log_backtrace_mode, backtrace_min_level and backtrace_functions.
+ */
+static bool
+matches_backtrace_gucs(ErrorData *edata)
+{
+	if (log_backtrace == LOGBACKTRACE_NONE)
+		return false;
+
+	if (log_backtrace == LOGBACKTRACE_INTERNAL_ERROR &&
+		edata->sqlerrcode != ERRCODE_INTERNAL_ERROR)
+		return false;
+
+	if (backtrace_min_level > edata->elevel)
+		return false;
+
+	return matches_backtrace_functions(edata->funcname);
+}
+
 /*
  * matches_backtrace_functions --- checks whether the given funcname matches
  * backtrace_functions
@@ -827,6 +846,9 @@ matches_backtrace_functions(const char *funcname)
 {
 	const char *p;
 
+	if (!backtrace_functions || backtrace_functions[0] == '\0')
+		return true;
+
 	if (!backtrace_function_list || funcname == NULL || funcname[0] == '\0')
 		return false;
 

src/backend/utils/misc/guc_tables.c

@@ -163,6 +163,23 @@ static const struct config_enum_entry server_message_level_options[] = {
 	{NULL, 0, false}
 };
 
+static const struct config_enum_entry backtrace_level_options[] = {
+	{"debug5", DEBUG5, false},
+	{"debug4", DEBUG4, false},
+	{"debug3", DEBUG3, false},
+	{"debug2", DEBUG2, false},
+	{"debug1", DEBUG1, false},
+	{"debug", DEBUG2, true},
+	{"log", LOG, false},
+	{"info", INFO, true},
+	{"notice", NOTICE, false},
+	{"warning", WARNING, false},
+	{"error", ERROR, false},
+	{"fatal", FATAL, false},
+	{"panic", PANIC, false},
+	{NULL, 0, false}
+};
+
 static const struct config_enum_entry intervalstyle_options[] = {
 	{"postgres", INTSTYLE_POSTGRES, false},
 	{"postgres_verbose", INTSTYLE_POSTGRES_VERBOSE, false},
@@ -200,6 +217,16 @@ static const struct config_enum_entry log_error_verbosity_options[] = {
 StaticAssertDecl(lengthof(log_error_verbosity_options) == (PGERROR_VERBOSE + 2),
 				 "array length mismatch");
 
+static const struct config_enum_entry log_backtrace_options[] = {
+	{"none", LOGBACKTRACE_NONE, false},
+	{"internal_error", LOGBACKTRACE_INTERNAL_ERROR, false},
+	{"all", LOGBACKTRACE_ALL, false},
+	{NULL, 0, false}
+};
+
+StaticAssertDecl(lengthof(log_backtrace_options) == (LOGBACKTRACE_ALL + 2),
+				 "array length mismatch");
+
 static const struct config_enum_entry log_statement_options[] = {
 	{"none", LOGSTMT_NONE, false},
 	{"ddl", LOGSTMT_DDL, false},
@@ -546,6 +573,7 @@ int			log_temp_files = -1;
 double		log_statement_sample_rate = 1.0;
 double		log_xact_sample_rate = 0;
 char	   *backtrace_functions;
+int			backtrace_min_level = ERROR;
 
 int			temp_file_limit = -1;
 
@@ -5004,6 +5032,18 @@ struct config_enum ConfigureNamesEnum[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"backtrace_min_level", PGC_SUSET, DEVELOPER_OPTIONS,
+			gettext_noop("Sets the message levels that create backtraces when log_backtrace is configured."),
+			gettext_noop("Each level includes all the levels that follow it. The later"
+						 " the level, the fewer backtraces are created."),
+			GUC_NOT_IN_SAMPLE
+		},
+		&backtrace_min_level,
+		ERROR, backtrace_level_options,
+		NULL, NULL, NULL
+	},
+
 	{
 		{"bytea_output", PGC_USERSET, CLIENT_CONN_STATEMENT,
 			gettext_noop("Sets the output format for bytea."),
@@ -5100,6 +5140,16 @@ struct config_enum ConfigureNamesEnum[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"log_backtrace", PGC_SUSET, LOGGING_WHAT,
+			gettext_noop("Sets if logs should include a backtrace."),
+			NULL
+		},
+		&log_backtrace,
+		LOGBACKTRACE_NONE, log_backtrace_options,
+		NULL, NULL, NULL
+	},
+
 	{
 		{"log_error_verbosity", PGC_SUSET, LOGGING_WHAT,
 			gettext_noop("Sets the verbosity of logged messages."),

src/backend/utils/misc/postgresql.conf.sample

@@ -594,6 +594,7 @@
 					# their durations, > 0 logs only
 					# actions running at least this number
 					# of milliseconds.
+#log_backtrace = 'none'
 #log_checkpoints = on
 #log_connections = '' # log aspects of connection setup
           # options include receipt, authentication, authorization,

src/include/utils/elog.h

@@ -487,9 +487,17 @@ typedef enum
 	PGERROR_VERBOSE,			/* all the facts, ma'am */
 } PGErrorVerbosity;
 
+enum
+{
+	LOGBACKTRACE_NONE,			/* no backtrace */
+	LOGBACKTRACE_INTERNAL_ERROR,	/* backtrace for internal error code */
+	LOGBACKTRACE_ALL,			/* backtrace for all logs */
+};
+
 extern PGDLLIMPORT int Log_error_verbosity;
 extern PGDLLIMPORT char *Log_line_prefix;
 extern PGDLLIMPORT int Log_destination;
+extern PGDLLIMPORT int log_backtrace;
 extern PGDLLIMPORT char *Log_destination_string;
 extern PGDLLIMPORT bool syslog_sequence_numbers;
 extern PGDLLIMPORT bool syslog_split_messages;

src/include/utils/guc.h

@@ -279,6 +279,7 @@ extern PGDLLIMPORT int log_temp_files;
 extern PGDLLIMPORT double log_statement_sample_rate;
 extern PGDLLIMPORT double log_xact_sample_rate;
 extern PGDLLIMPORT char *backtrace_functions;
+extern PGDLLIMPORT int backtrace_min_level;
 
 extern PGDLLIMPORT int temp_file_limit;