diff --git a/src/backend/nodes/params.c b/src/backend/nodes/params.c
index 13d90f6551..a881df578e 100644
--- a/src/backend/nodes/params.c
+++ b/src/backend/nodes/params.c
@@ -23,6 +23,7 @@
 #include "utils/datum.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
+#include "utils/portal.h"
 
 
 /*
@@ -361,14 +362,17 @@ BuildParamLogString(ParamListInfo params, char **knownTextValues)
 void
 ParamsErrorCallback(void *arg)
 {
-	ParamListInfo params = (ParamListInfo) arg;
+	ParamsErrorCbData *data = (ParamsErrorCbData *) arg;
 
-	if (params == NULL || params->paramValuesStr == NULL)
+	if (data == NULL ||
+		data->params == NULL ||
+		data->params->paramValuesStr == NULL)
 		return;
 
-	/*
-	 * XXX this clobbers any other DETAIL line that the error callsite could
-	 * have had.  Do we care?
-	 */
-	errdetail("parameters: %s", params->paramValuesStr);
+	if (data->portalName && data->portalName[0] != '\0')
+		errcontext("extended query \"%s\" with parameters: %s",
+				   data->portalName, data->params->paramValuesStr);
+	else
+		errcontext("extended query with parameters: %s",
+				   data->params->paramValuesStr);
 }
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 9a009a5a9b..05a03ae924 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -1753,7 +1753,7 @@ exec_bind_message(StringInfo input_message)
 	 */
 	if (numParams > 0)
 	{
-		char	  **knownTextValues = NULL;
+		char	  **knownTextValues = NULL;	/* allocate on first use */
 
 		params = makeParamList(numParams);
 
@@ -1822,22 +1822,19 @@ exec_bind_message(StringInfo input_message)
 
 				pval = OidInputFunctionCall(typinput, pstring, typioparam, -1);
 
-				/*
-				 * Save the parameter string if we need it; otherwise free it.
-				 */
+				/* When logging params, save a copy for later. */
 				if (pstring)
 				{
 					if (log_parameters_on_error)
 					{
-						/*
-						 * Allocate this on first use, making sure to put it
-						 * in a short-lived context.
-						 */
 						if (knownTextValues == NULL)
 							knownTextValues =
 								MemoryContextAllocZero(MessageContext,
 													   numParams * sizeof(char *));
-						knownTextValues[paramno] = pstring;
+						knownTextValues[paramno] =
+							pstring == pbuf.data ?
+							MemoryContextStrdup(MessageContext, pstring) :
+							pstring;
 					}
 					else if (pstring != pbuf.data)
 						pfree(pstring);
@@ -1905,7 +1902,8 @@ exec_bind_message(StringInfo input_message)
 	/* Set the error callback so that parameters are logged, as needed  */
 	params_errcxt.previous = error_context_stack;
 	params_errcxt.callback = ParamsErrorCallback;
-	params_errcxt.arg = (void *) params;
+	params_errcxt.arg = (void *) &((ParamsErrorCbData)
+								   { portal->name, params });
 	error_context_stack = &params_errcxt;
 
 	/* Get the result format codes */
@@ -2145,7 +2143,8 @@ exec_execute_message(const char *portal_name, long max_rows)
 	 */
 	params_errcxt.previous = error_context_stack;
 	params_errcxt.callback = ParamsErrorCallback;
-	params_errcxt.arg = (void *) portalParams;
+	params_errcxt.arg = (void *) &((ParamsErrorCbData)
+								   { portal->name, portalParams });
 	error_context_stack = &params_errcxt;
 
 	if (max_rows <= 0)
diff --git a/src/include/nodes/params.h b/src/include/nodes/params.h
index ba51dfe5e0..1e557ca7fd 100644
--- a/src/include/nodes/params.h
+++ b/src/include/nodes/params.h
@@ -150,6 +150,12 @@ typedef struct ParamExecData
 	bool		isnull;
 } ParamExecData;
 
+/* type of argument for ParamsErrorCallback */
+typedef struct ParamsErrorCbData
+{
+	const char	 *portalName;
+	ParamListInfo params;
+} ParamsErrorCbData;
 
 /* Functions found in src/backend/nodes/params.c */
 extern ParamListInfo makeParamList(int numParams);