log_parameter_max_length_v001.patch

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index c1128f89ec..0f40246c2d 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -6645,6 +6645,28 @@ log_line_prefix = '%m [%p] %q%u@%d/%a '
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-log-parameter-max-length" xreflabel="log_parameter_max_length">
+      <term><varname>log_parameter_max_length</varname> (<type>boolean</type>)
+      <indexterm>
+       <primary><varname>log_parameter_max_length</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+      <listitem>
+       <para>
+        Controls whether to log parameters in full or cut them to a certain length.
+        Bind parameters can appear in the log as a result of 
+        <xref linkend="guc-log-min-duration-statement"/>,
+        <xref linkend="guc-log-statement"/> or
+        <xref linkend="guc-log-parameters-on_error"/>
+        settings.
+        Zero (the default) disables cutting.
+        If this value is specified without units, it is taken as bytes.
+        Due to multibyte character and ellipsis, truncated values may be slightly shorter.
+        Only superusers can change this setting.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry id="guc-log-statement" xreflabel="log_statement">
       <term><varname>log_statement</varname> (<type>enum</type>)
       <indexterm>
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 0a6f80963b..acc31899d6 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -1839,13 +1839,22 @@ exec_bind_message(StringInfo input_message)
 						if (knownTextValues == NULL)
 							knownTextValues =
 								palloc0(numParams * sizeof(char *));
-						/*
-						 * Note: must copy at least two more full characters
-						 * than BuildParamLogString wants to see; otherwise it
-						 * might fail to include the ellipsis.
-						 */
-						knownTextValues[paramno] =
-							pnstrdup(pstring, 64 + 2 * MAX_MULTIBYTE_CHAR_LEN);
+
+						if (log_parameter_max_length != 0)
+						{
+							/*
+							* Note: must copy at least two more full characters
+							* than BuildParamLogString wants to see;
+							* otherwise it might fail to include the ellipsis.
+							*/
+							knownTextValues[paramno] =
+								pnstrdup(pstring,
+										 log_parameter_max_length
+											+ 2 * MAX_MULTIBYTE_CHAR_LEN);
+						}
+						else
+							knownTextValues[paramno] = pstrdup(pstring);
+
 						MemoryContextSwitchTo(oldcxt);
 					}
 					if (pstring != pbuf.data)
@@ -1908,7 +1917,9 @@ exec_bind_message(StringInfo input_message)
 		 */
 		if (log_parameters_on_error)
 			params->paramValuesStr =
-				BuildParamLogString(params, knownTextValues, 64);
+				BuildParamLogString(params,
+									knownTextValues,
+									log_parameter_max_length);
 	}
 	else
 		params = NULL;
@@ -2397,7 +2408,7 @@ errdetail_params(ParamListInfo params)
 	{
 		char   *str;
 
-		str = BuildParamLogString(params, NULL, 0);
+		str = BuildParamLogString(params, NULL, log_parameter_max_length);
 		if (str && str[0] != '\0')
 			errdetail("parameters: %s", str);
 	}
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 8228e1f390..f27efc6c24 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -543,6 +543,7 @@ int			log_min_messages = WARNING;
 int			client_min_messages = NOTICE;
 int			log_min_duration_sample = -1;
 int			log_min_duration_statement = -1;
+int			log_parameter_max_length = 0;
 int			log_temp_files = -1;
 double		log_statement_sample_rate = 1.0;
 double		log_xact_sample_rate = 0;
@@ -2834,6 +2835,17 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"log_parameter_max_length", PGC_SUSET, LOGGING_WHAT,
+			gettext_noop("When logging a parameter value, only log first N bytes."),
+			gettext_noop("Zero to print values in full."),
+			GUC_UNIT_BYTE
+		},
+		&log_parameter_max_length,
+		0, 0, INT_MAX,
+		NULL, NULL, NULL
+	},
+
 	{
 		{"bgwriter_delay", PGC_SIGHUP, RESOURCES_BGWRITER,
 			gettext_noop("Background writer sleep time between rounds."),
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ce93ace76c..72ab683ac6 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -235,6 +235,7 @@ typedef enum
 /* GUC vars that are actually declared in guc.c, rather than elsewhere */
 extern bool log_duration;
 extern bool log_parameters_on_error;
+extern int log_parameter_max_length;
 extern bool Debug_print_plan;
 extern bool Debug_print_parse;
 extern bool Debug_print_rewritten;