diff -u src/backend/access/transam/xact.c src/backend/access/transam/xact.c
--- src/backend/access/transam/xact.c	16 Jul 2004 05:40:09 -0000
+++ src/backend/access/transam/xact.c	16 Jul 2004 07:04:35 -0000
@@ -159,6 +159,8 @@
 #include "commands/user.h"
 #include "executor/spi.h"
 #include "libpq/be-fsstubs.h"
+#include "lib/stringinfo.h"
+#include "libpq/pqformat.h"
 #include "miscadmin.h"
 #include "storage/fd.h"
 #include "storage/proc.h"
@@ -341,6 +343,7 @@
 static void ShowTransactionStateRec(TransactionState state);
 static const char *BlockStateAsString(TBlockState blockState);
 static const char *TransStateAsString(TransState state);
+static void SendTransactionNestingLevel(void);
 
 /* ----------------------------------------------------------------
  *	transaction state accessors
@@ -1360,6 +1369,8 @@
 	 */
 	s->state = TRANS_INPROGRESS;
 
+	SendTransactionNestingLevel();
+
 	ShowTransactionState("StartTransaction");
 }
 
@@ -1486,6 +1508,8 @@
 	 */
 	s->state = TRANS_DEFAULT;
 
+	SendTransactionNestingLevel();
+
 	RESUME_INTERRUPTS();
 }
 
@@ -1627,6 +1651,8 @@
 	s->nestingLevel = 0;
 	s->childXids = NIL;
 
+	SendTransactionNestingLevel();
+
 	/*
 	 * done with abort processing, set current transaction state back to
 	 * default
@@ -2741,6 +2767,8 @@
 			s->blockState != TBLOCK_SUBENDABORT_ALL)
 		AbortSubTransaction();
 	s->blockState = TBLOCK_SUBABORT;
+
+	SendTransactionNestingLevel();
 }
 
 /*
@@ -2762,6 +2790,8 @@
 		PopTransaction();
 		s = CurrentTransactionState;				/* changed by pop */
 	}
+
+	SendTransactionNestingLevel();
 }
 
 /*
@@ -2893,15 +2930,17 @@
 	/* Initialize the various transaction subsystems */
 	AtSubStart_Memory();
 	AtSubStart_Inval();
	AtSubStart_RelationCache();
	AtSubStart_CatCache();
	AtSubStart_Buffers();
 	AtSubStart_smgr();
 	AtSubStart_Notify();
 	DeferredTriggerBeginSubXact();
 
 	s->state = TRANS_INPROGRESS;
 
+	SendTransactionNestingLevel();
+
 	ShowTransactionState("StartSubTransaction");
 }
 
@@ -2942,11 +2981,13 @@
 	AtEOSubXact_on_commit_actions(true, s->transactionIdData,
 								  s->parent->transactionIdData);
 
	AtEOSubXact_CatCache(true);
	AtEOSubXact_RelationCache(true);
	AtEOSubXact_Buffers(true);
 	AtSubCommit_Memory();
 
+	SendTransactionNestingLevel();
+
 	s->state = TRANS_DEFAULT;
 }
 
@@ -3045,6 +3087,8 @@
 	AtSubCleanup_Portals();
 	AtSubCleanup_Memory();
 
+	SendTransactionNestingLevel();
+
 	s->state = TRANS_DEFAULT;
 }
 
@@ -3160,6 +3204,22 @@
 	pfree(s);
 }
 
+static void
+SendTransactionNestingLevel(void)
+{
+	char	*val = (char *)palloc(12);
+	StringInfoData msgbuf;
+
+	snprintf(val, 12, "%d", CurrentTransactionState->nestingLevel);
+
+	pq_beginmessage(&msgbuf, 'S');
+	pq_sendstring(&msgbuf, "nesting_level");
+	pq_sendstring(&msgbuf, val);
+	pq_endmessage(&msgbuf);
+
+	pfree(val);
+}
+
 /*
  * ShowTransactionState
  *		Debug support
--- src/bin/psql/prompt.c	24 Feb 2004 21:45:18 -0000	1.35
+++ src/bin/psql/prompt.c	16 Jul 2004 06:39:33 -0000
@@ -46,6 +46,7 @@
  *		in prompt2 -, *, ', or ";
  *		in prompt3 nothing
  * %x - transaction status: empty, *, !, ? (unknown or no connection)
+ * %d - transaction nesting level
  * %? - the error code of the last query (not yet implemented)
  * %% - a percent sign
  *
@@ -237,6 +238,13 @@
 						}
 					break;
 
+				case 'd':
+					if (!pset.db)
+						buf[0] = '?';
+					else
+						snprintf(buf, MAX_PROMPT_SIZE, "%d", PQnestingLevel(pset.db));
+					break;
+
 				case '?':
 					/* not here yet */
 					break;
--- src/interfaces/libpq/fe-connect.c	12 Jul 2004 14:23:28 -0000	1.278
+++ src/interfaces/libpq/fe-connect.c	16 Jul 2004 06:35:31 -0000
@@ -2847,6 +2847,14 @@
 	return conn->xactStatus;
 }
 
+int
+PQnestingLevel(const PGconn *conn)
+{
+	if (!conn || conn->status != CONNECTION_OK)
+		return -1;
+	return conn->nestingLevel;
+}
+
 const char *
 PQparameterStatus(const PGconn *conn, const char *paramName)
 {
only in patch2:
unchanged:
--- src/interfaces/libpq/fe-exec.c	7 May 2004 00:24:59 -0000	1.159
+++ src/interfaces/libpq/fe-exec.c	16 Jul 2004 06:59:53 -0000
@@ -613,6 +613,8 @@
 	 */
 	if (strcmp(name, "client_encoding") == 0)
 		conn->client_encoding = pg_char_to_encoding(value);
+	else if (strcmp(name, "nesting_level") == 0)
+		conn->nestingLevel = atoi(value);
 	else if (strcmp(name, "server_version") == 0)
 	{
 		int			cnt;
only in patch2:
unchanged:
--- src/interfaces/libpq/libpq-fe.h	24 Mar 2004 03:44:59 -0000	1.104
+++ src/interfaces/libpq/libpq-fe.h	16 Jul 2004 06:37:06 -0000
@@ -245,6 +245,7 @@
 extern char *PQoptions(const PGconn *conn);
 extern ConnStatusType PQstatus(const PGconn *conn);
 extern PGTransactionStatusType PQtransactionStatus(const PGconn *conn);
+extern int	PQnestingLevel(const PGconn *conn);
 extern const char *PQparameterStatus(const PGconn *conn,
 				  const char *paramName);
 extern int	PQprotocolVersion(const PGconn *conn);
only in patch2:
unchanged:
--- src/interfaces/libpq/libpq-int.h	31 May 2004 18:42:40 -0000	1.88
+++ src/interfaces/libpq/libpq-int.h	16 Jul 2004 06:36:07 -0000
@@ -265,6 +265,7 @@
 	PGAsyncStatusType asyncStatus;
 	PGTransactionStatusType xactStatus;
 	/* note: xactStatus never changes to ACTIVE */
+	int			nestingLevel;	/* transaction nesting level */
 	bool		nonblocking;	/* whether this connection is using
 								 * nonblock sending semantics */
 	bool		ext_query;		/* was our last query sent with extended