diff --git a/src/backend/libpq/be-secure-gssapi.c b/src/backend/libpq/be-secure-gssapi.c
index 6089d627ab..818da567a3 100644
--- a/src/backend/libpq/be-secure-gssapi.c
+++ b/src/backend/libpq/be-secure-gssapi.c
@@ -14,8 +14,9 @@
 
 #include "postgres.h"
 
-#include "be-gssapi-common.h"
+#include <unistd.h>
 
+#include "be-gssapi-common.h"
 #include "libpq/auth.h"
 #include "libpq/libpq.h"
 #include "libpq/libpq-be.h"
@@ -23,8 +24,6 @@
 #include "miscadmin.h"
 #include "pgstat.h"
 
-#include <unistd.h>
-
 
 /*
  * Handle the encryption/decryption of data using GSSAPI.
@@ -179,10 +178,13 @@ be_gssapi_write(Port *port, void *ptr, size_t len)
 			pg_GSS_error(FATAL, gettext_noop("GSSAPI wrap error"), major, minor);
 
 		if (conf == 0)
-			ereport(FATAL, (errmsg("GSSAPI did not provide confidentiality")));
+			ereport(FATAL,
+					(errmsg("GSSAPI did not provide confidentiality")));
 
 		if (output.length > PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32))
-			ereport(FATAL, (errmsg("GSSAPI tried to send packet of size: %ld", output.length)));
+			ereport(FATAL,
+					(errmsg("server tried to send oversize GSSAPI packet: %zu bytes",
+							(size_t) output.length)));
 
 		bytes_encrypted += input.length;
 		bytes_to_encrypt -= input.length;
@@ -297,7 +299,9 @@ be_gssapi_read(Port *port, void *ptr, size_t len)
 
 		/* Check for over-length packet */
 		if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
-			ereport(FATAL, (errmsg("Over-size GSSAPI packet sent by the client.")));
+			ereport(FATAL,
+					(errmsg("oversize GSSAPI packet sent by the client: %zu bytes",
+							(size_t) input.length)));
 
 		/*
 		 * Read as much of the packet as we are able to on this call into
@@ -341,7 +345,8 @@ be_gssapi_read(Port *port, void *ptr, size_t len)
 						 major, minor);
 
 		if (conf == 0)
-			ereport(FATAL, (errmsg("GSSAPI did not provide confidentiality")));
+			ereport(FATAL,
+					(errmsg("GSSAPI did not provide confidentiality")));
 
 		memcpy(PqGSSResultBuffer, output.value, output.length);
 
@@ -492,7 +497,9 @@ secure_open_gssapi(Port *port)
 		 * Verify on our side that the client doesn't do something funny.
 		 */
 		if (input.length > PQ_GSS_RECV_BUFFER_SIZE)
-			ereport(FATAL, (errmsg("Over-size GSSAPI packet sent by the client: %ld", input.length)));
+			ereport(FATAL,
+					(errmsg("oversize GSSAPI packet sent by the client: %zu bytes",
+							(size_t) input.length)));
 
 		/*
 		 * Get the rest of the packet so we can pass it to GSSAPI to accept
@@ -538,7 +545,9 @@ secure_open_gssapi(Port *port)
 			uint32		netlen = htonl(output.length);
 
 			if (output.length > PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32))
-				ereport(FATAL, (errmsg("GSSAPI tried to send oversize packet")));
+				ereport(FATAL,
+						(errmsg("server tried to send oversize GSSAPI packet: %zu bytes",
+								(size_t) output.length)));
 
 			memcpy(PqGSSSendBuffer, (char *) &netlen, sizeof(uint32));
 			PqGSSSendPointer += sizeof(uint32);
diff --git a/src/interfaces/libpq/fe-secure-gssapi.c b/src/interfaces/libpq/fe-secure-gssapi.c
index ec2a4c6478..6111439ff0 100644
--- a/src/interfaces/libpq/fe-secure-gssapi.c
+++ b/src/interfaces/libpq/fe-secure-gssapi.c
@@ -16,7 +16,6 @@
 #include "libpq-fe.h"
 #include "libpq-int.h"
 #include "fe-gssapi-common.h"
-
 #include "port/pg_bswap.h"
 
 /*
@@ -163,15 +162,16 @@ pg_GSS_write(PGconn *conn, const void *ptr, size_t len)
 		}
 		else if (conf == 0)
 		{
-			printfPQExpBuffer(&conn->errorMessage, libpq_gettext(
-																 "GSSAPI did not provide confidentiality\n"));
+			printfPQExpBuffer(&conn->errorMessage,
+							  libpq_gettext("GSSAPI did not provide confidentiality\n"));
 			goto cleanup;
 		}
 
 		if (output.length > PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32))
 		{
-			printfPQExpBuffer(&conn->errorMessage, libpq_gettext(
-																 "GSSAPI attempt to send oversize packet\n"));
+			printfPQExpBuffer(&conn->errorMessage,
+							  libpq_gettext("client tried to send oversize GSSAPI packet: %zu bytes\n"),
+							  (size_t) output.length);
 			goto cleanup;
 		}
 
@@ -286,8 +286,8 @@ pg_GSS_read(PGconn *conn, void *ptr, size_t len)
 		/* Check for over-length packet */
 		if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
 		{
-			printfPQExpBuffer(&conn->errorMessage, libpq_gettext(
-																 "GSSAPI did not provide confidentiality\n"));
+			printfPQExpBuffer(&conn->errorMessage,
+							  libpq_gettext("GSSAPI did not provide confidentiality\n"));
 			ret = -1;
 			goto cleanup;
 		}
@@ -328,8 +328,8 @@ pg_GSS_read(PGconn *conn, void *ptr, size_t len)
 		}
 		else if (conf == 0)
 		{
-			printfPQExpBuffer(&conn->errorMessage, libpq_gettext(
-																 "GSSAPI did not provide confidentiality\n"));
+			printfPQExpBuffer(&conn->errorMessage,
+							  libpq_gettext("GSSAPI did not provide confidentiality\n"));
 			ret = -1;
 			goto cleanup;
 		}
@@ -476,7 +476,7 @@ pqsecure_open_gss(PGconn *conn)
 
 			PqGSSRecvLength += ret;
 
-			printfPQExpBuffer(&conn->errorMessage, "%s", PqGSSRecvBuffer + 1);
+			printfPQExpBuffer(&conn->errorMessage, "%s\n", PqGSSRecvBuffer + 1);
 
 			return PGRES_POLLING_FAILED;
 		}
@@ -490,7 +490,9 @@ pqsecure_open_gss(PGconn *conn)
 		input.length = ntohl(*(uint32 *) PqGSSRecvBuffer);
 		if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
 		{
-			printfPQExpBuffer(&conn->errorMessage, libpq_gettext("Over-size GSSAPI packet sent by the server: %ld"), input.length);
+			printfPQExpBuffer(&conn->errorMessage,
+							  libpq_gettext("oversize GSSAPI packet sent by the server: %zu bytes\n"),
+							  (size_t) input.length);
 			return PGRES_POLLING_FAILED;
 		}