postgres
diff --git a/‎doc/src/sgml/ref/psql-ref.sgml
Lines changed: 4 additions & 3 deletions b/‎doc/src/sgml/ref/psql-ref.sgml
Lines changed: 4 additions & 3 deletions
diff --git a/‎src/bin/psql/command.c
Lines changed: 27 additions & 5 deletions b/‎src/bin/psql/command.c
Lines changed: 27 additions & 5 deletions
diff --git a/‎src/bin/psql/common.c
Lines changed: 14 additions & 5 deletions b/‎src/bin/psql/common.c
Lines changed: 14 additions & 5 deletions
diff --git a/‎src/bin/psql/common.h
Lines changed: 1 addition & 1 deletion b/‎src/bin/psql/common.h
Lines changed: 1 addition & 1 deletion
diff --git a/‎src/bin/psql/help.c
Lines changed: 3 additions & 1 deletion b/‎src/bin/psql/help.c
Lines changed: 3 additions & 1 deletion
diff --git a/‎src/bin/psql/t/001_basic.pl
Lines changed: 23 additions & 0 deletions b/‎src/bin/psql/t/001_basic.pl
Lines changed: 23 additions & 0 deletions
@@ -3566,13 +3566,14 @@ testdb=&gt; <userinput>\setenv LESS -imx4F</userinput>
 
 
       <varlistentry id="app-psql-meta-command-watch">
-        <term><literal>\watch [ i[nterval]=<replaceable class="parameter">seconds</replaceable> ] [ c[ount]=<replaceable class="parameter">times</replaceable> ] [ <replaceable class="parameter">seconds</replaceable> ]</literal></term>
+        <term><literal>\watch [ i[nterval]=<replaceable class="parameter">seconds</replaceable> ] [ c[ount]=<replaceable class="parameter">times</replaceable> ] [ m[in_rows]=<replaceable class="parameter">rows</replaceable> ] [ <replaceable class="parameter">seconds</replaceable> ]</literal></term>
         <listitem>
         <para>
         Repeatedly execute the current query buffer (as <literal>\g</literal> does)
         until interrupted, or the query fails, or the execution count limit
-        (if given) is reached.  Wait the specified number of
-        seconds (default 2) between executions.  For backwards compatibility,
+        (if given) is reached, or the query no longer returns the minimum number
+        of rows. Wait the specified number of seconds (default 2) between executions.
+        For backwards compatibility,
         <replaceable class="parameter">seconds</replaceable> can be specified
         with or without an <literal>interval=</literal> prefix.
         Each query result is
 
@@ -162,7 +162,7 @@ static bool do_connect(enum trivalue reuse_previous_specification,
 static bool do_edit(const char *filename_arg, PQExpBuffer query_buf,
 					int lineno, bool discard_on_quit, bool *edited);
 static bool do_shell(const char *command);
-static bool do_watch(PQExpBuffer query_buf, double sleep, int iter);
+static bool do_watch(PQExpBuffer query_buf, double sleep, int iter, int min_rows);
 static bool lookup_object_oid(EditableObjectType obj_type, const char *desc,
 							  Oid *obj_oid);
 static bool get_create_object_cmd(EditableObjectType obj_type, Oid oid,
@@ -2775,13 +2775,15 @@ exec_command_watch(PsqlScanState scan_state, bool active_branch,
 	{
 		bool		have_sleep = false;
 		bool		have_iter = false;
+		bool		have_min_rows = false;
 		double		sleep = 2;
 		int			iter = 0;
+		int			min_rows = 0;
 
 		/*
 		 * Parse arguments.  We allow either an unlabeled interval or
 		 * "name=value", where name is from the set ('i', 'interval', 'c',
-		 * 'count').
+		 * 'count', 'm', 'min_rows').
 		 */
 		while (success)
 		{
@@ -2838,6 +2840,26 @@ exec_command_watch(PsqlScanState scan_state, bool active_branch,
 						}
 					}
 				}
+				else if (strncmp("m=", opt, strlen("m=")) == 0 ||
+						 strncmp("min_rows=", opt, strlen("min_rows=")) == 0)
+				{
+					if (have_min_rows)
+					{
+						pg_log_error("\\watch: minimum row count specified more than once");
+						success = false;
+					}
+					else
+					{
+						have_min_rows = true;
+						errno = 0;
+						min_rows = strtoint(valptr, &opt_end, 10);
+						if (min_rows <= 0 || *opt_end || errno == ERANGE)
+						{
+							pg_log_error("\\watch: incorrect minimum row count \"%s\"", valptr);
+							success = false;
+						}
+					}
+				}
 				else
 				{
 					pg_log_error("\\watch: unrecognized parameter \"%s\"", opt);
@@ -2874,7 +2896,7 @@ exec_command_watch(PsqlScanState scan_state, bool active_branch,
 			/* If query_buf is empty, recall and execute previous query */
 			(void) copy_previous_query(query_buf, previous_buf);
 
-			success = do_watch(query_buf, sleep, iter);
+			success = do_watch(query_buf, sleep, iter, min_rows);
 		}
 
 		/* Reset the query buffer as though for \r */
@@ -5144,7 +5166,7 @@ do_shell(const char *command)
  * onto a bunch of exec_command's variables to silence stupider compilers.
  */
 static bool
-do_watch(PQExpBuffer query_buf, double sleep, int iter)
+do_watch(PQExpBuffer query_buf, double sleep, int iter, int min_rows)
 {
 	long		sleep_ms = (long) (sleep * 1000);
 	printQueryOpt myopt = pset.popt;
@@ -5274,7 +5296,7 @@ do_watch(PQExpBuffer query_buf, double sleep, int iter)
 		myopt.title = title;
 
 		/* Run the query and print out the result */
-		res = PSQLexecWatch(query_buf->data, &myopt, pagerpipe);
+		res = PSQLexecWatch(query_buf->data, &myopt, pagerpipe, min_rows);
 
 		/*
 		 * PSQLexecWatch handles the case where we can no longer repeat the
 
@@ -36,6 +36,7 @@ static int	ExecQueryAndProcessResults(const char *query,
 									   double *elapsed_msec,
 									   bool *svpt_gone_p,
 									   bool is_watch,
+									   int min_rows,
 									   const printQueryOpt *opt,
 									   FILE *printQueryFout);
 static bool command_no_begin(const char *query);
@@ -632,7 +633,7 @@ PSQLexec(const char *query)
  * e.g., because of the interrupt, -1 on error.
  */
 int
-PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout)
+PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout, int min_rows)
 {
 	bool		timing = pset.timing;
 	double		elapsed_msec = 0;
@@ -646,7 +647,7 @@ PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout)
 
 	SetCancelConn(pset.db);
 
-	res = ExecQueryAndProcessResults(query, &elapsed_msec, NULL, true, opt, printQueryFout);
+	res = ExecQueryAndProcessResults(query, &elapsed_msec, NULL, true, min_rows, opt, printQueryFout);
 
 	ResetCancelConn();
 
@@ -1134,7 +1135,7 @@ SendQuery(const char *query)
 			 pset.crosstab_flag || !is_select_command(query))
 	{
 		/* Default fetch-it-all-and-print mode */
-		OK = (ExecQueryAndProcessResults(query, &elapsed_msec, &svpt_gone, false, NULL, NULL) > 0);
+		OK = (ExecQueryAndProcessResults(query, &elapsed_msec, &svpt_gone, false, 0, NULL, NULL) > 0);
 	}
 	else
 	{
@@ -1415,11 +1416,12 @@ DescribeQuery(const char *query, double *elapsed_msec)
 static int
 ExecQueryAndProcessResults(const char *query,
 						   double *elapsed_msec, bool *svpt_gone_p,
-						   bool is_watch,
+						   bool is_watch, int min_rows,
 						   const printQueryOpt *opt, FILE *printQueryFout)
 {
 	bool		timing = pset.timing;
 	bool		success;
+	bool		return_early = false;
 	instr_time	before,
 				after;
 	PGresult   *result;
@@ -1461,6 +1463,10 @@ ExecQueryAndProcessResults(const char *query,
 
 	/* first result */
 	result = PQgetResult(pset.db);
+	if (min_rows > 0 && PQntuples(result) < min_rows)
+	{
+		return_early = true;
+	}
 
 	while (result != NULL)
 	{
@@ -1683,7 +1689,10 @@ ExecQueryAndProcessResults(const char *query,
 	if (!CheckConnection())
 		return -1;
 
-	return cancel_pressed ? 0 : success ? 1 : -1;
+	if (cancel_pressed || return_early)
+		return 0;
+
+	return success ? 1 : -1;
 }
 
 
 
@@ -32,7 +32,7 @@ extern void psql_setup_cancel_handler(void);
 extern void SetShellResultVariables(int wait_result);
 
 extern PGresult *PSQLexec(const char *query);
-extern int	PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout);
+extern int	PSQLexecWatch(const char *query, const printQueryOpt *opt, FILE *printQueryFout, int min_rows);
 
 extern bool SendQuery(const char *query);
 
 
@@ -200,7 +200,9 @@ slashUsage(unsigned short int pager)
 	HELP0("  \\gset [PREFIX]         execute query and store result in psql variables\n");
 	HELP0("  \\gx [(OPTIONS)] [FILE] as \\g, but forces expanded output mode\n");
 	HELP0("  \\q                     quit psql\n");
-	HELP0("  \\watch [[i=]SEC] [c=N] execute query every SEC seconds, up to N times\n");
+	HELP0("  \\watch [[i=]SEC] [c=N] [m=MIN]\n");
+	HELP0("                          execute query every SEC seconds, up to N times\n");
+	HELP0("  
1C6A
                        stop if less than MIN rows are returned\n");
 	HELP0("\n");
 
 	HELP0("Help\n");
 
@@ -355,6 +355,29 @@ sub psql_fails_like
 psql_like($node, sprintf('SELECT 1 \watch c=3 i=%g', 0.01),
 	qr/1\n1\n1/, '\watch with 3 iterations');
 
+# Check \watch minimum row count
+psql_fails_like(
+	$node,
+	'SELECT 3 \watch m=x',
+	qr/incorrect minimum row count/,
+	'\watch, invalid minimum row setting');
+
+psql_fails_like(
+	$node,
+	'SELECT 3 \watch m=1 min_rows=2',
+	qr/minimum row count specified more than once/,
+	'\watch, minimum rows is specified more than once');
+
+psql_like(
+	$node,
+	q{with x as (
+		select now()-backend_start AS howlong
+		from pg_stat_activity
+		where pid = pg_backend_pid()
+	  ) select 123 from x where howlong < '2 seconds' \watch i=0.5 m=2},
+	qr/^123$/,
+	'\watch, 2 minimum rows');
+
 # Check \watch errors
 psql_fails_like(
 	$node,