diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 29bbec2188..53875afbf0 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -3551,12 +3551,16 @@ testdb=> \setenv LESS -imx4F
- \watch [ seconds ]
+ \watch [ i[nterval]=seconds ] [ c[ount]=times ] [ seconds ]
Repeatedly execute the current query buffer (as \g does)
- until interrupted or the query fails. Wait the specified number of
- seconds (default 2) between executions. Each query result is
+ 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,
+ seconds can be specified
+ with or without an interval= prefix.
+ Each query result is
displayed with a header that includes the \pset title
string (if any), the time as of query start, and the delay interval.
diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index d7731234b6..e8f583cac2 100644
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -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);
+static bool do_watch(PQExpBuffer query_buf, double sleep, int iter);
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,
@@ -2759,7 +2759,8 @@ exec_command_write(PsqlScanState scan_state, bool active_branch,
}
/*
- * \watch -- execute a query every N seconds
+ * \watch -- execute a query every N seconds.
+ * Optionally, stop after M iterations.
*/
static backslashResult
exec_command_watch(PsqlScanState scan_state, bool active_branch,
@@ -2769,32 +2770,109 @@ exec_command_watch(PsqlScanState scan_state, bool active_branch,
if (active_branch)
{
- char *opt = psql_scan_slash_option(scan_state,
- OT_NORMAL, NULL, true);
+ bool have_sleep = false;
+ bool have_iter = false;
double sleep = 2;
+ int iter = 0;
- /* Convert optional sleep-length argument */
- if (opt)
+ /*
+ * Parse arguments. We allow either an unlabeled interval or
+ * "name=value", where name is from the set ('i', 'interval', 'c',
+ * 'count').
+ */
+ while (success)
{
+ char *opt = psql_scan_slash_option(scan_state,
+ OT_NORMAL, NULL, true);
+ char *valptr;
char *opt_end;
- errno = 0;
- sleep = strtod(opt, &opt_end);
- if (sleep < 0 || *opt_end || errno == ERANGE)
+ if (!opt)
+ break; /* no more arguments */
+
+ valptr = strchr(opt, '=');
+ if (valptr)
{
- pg_log_error("\\watch: incorrect interval value '%s'", opt);
- free(opt);
- resetPQExpBuffer(query_buf);
- psql_scan_reset(scan_state);
- return PSQL_CMD_ERROR;
+ /* Labeled argument */
+ valptr++;
+ if (strncmp("i=", opt, strlen("i=")) == 0 ||
+ strncmp("interval=", opt, strlen("interval=")) == 0)
+ {
+ if (have_sleep)
+ {
+ pg_log_error("\\watch: interval value is specified more than once");
+ success = false;
+ }
+ else
+ {
+ have_sleep = true;
+ errno = 0;
+ sleep = strtod(valptr, &opt_end);
+ if (sleep < 0 || *opt_end || errno == ERANGE)
+ {
+ pg_log_error("\\watch: incorrect interval value \"%s\"", valptr);
+ success = false;
+ }
+ }
+ }
+ else if (strncmp("c=", opt, strlen("c=")) == 0 ||
+ strncmp("count=", opt, strlen("count=")) == 0)
+ {
+ if (have_iter)
+ {
+ pg_log_error("\\watch: iteration count is specified more than once");
+ success = false;
+ }
+ else
+ {
+ have_iter = true;
+ errno = 0;
+ iter = strtoint(valptr, &opt_end, 10);
+ if (iter <= 0 || *opt_end || errno == ERANGE)
+ {
+ pg_log_error("\\watch: incorrect iteration count \"%s\"", valptr);
+ success = false;
+ }
+ }
+ }
+ else
+ {
+ pg_log_error("\\watch: unrecognized parameter \"%s\"", opt);
+ success = false;
+ }
}
+ else
+ {
+ /* Unlabeled argument: take it as interval */
+ if (have_sleep)
+ {
+ pg_log_error("\\watch: interval value is specified more than once");
+ success = false;
+ }
+ else
+ {
+ have_sleep = true;
+ errno = 0;
+ sleep = strtod(opt, &opt_end);
+ if (sleep < 0 || *opt_end || errno == ERANGE)
+ {
+ pg_log_error("\\watch: incorrect interval value \"%s\"", opt);
+ success = false;
+ }
+ }
+ }
+
free(opt);
}
- /* If query_buf is empty, recall and execute previous query */
- (void) copy_previous_query(query_buf, previous_buf);
+ /* If we parsed arguments successfully, do the command */
+ if (success)
+ {
+ /* If query_buf is empty, recall and execute previous query */
+ (void) copy_previous_query(query_buf, previous_buf);
- success = do_watch(query_buf, sleep);
+ success = do_watch(query_buf, sleep, iter);
+ }
/* Reset the query buffer as though for \r */
resetPQExpBuffer(query_buf);
@@ -5071,7 +5149,7 @@ 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)
+do_watch(PQExpBuffer query_buf, double sleep, int iter)
{
long sleep_ms = (long) (sleep * 1000);
printQueryOpt myopt = pset.popt;
@@ -5204,6 +5282,10 @@ do_watch(PQExpBuffer query_buf, double sleep)
if (res <= 0)
break;
+ /* If we have iteration count, check that it's not exceeded yet */
+ if (iter && (--iter <= 0))
+ break;
+
if (pagerpipe && ferror(pagerpipe))
break;
diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 48fd51592a..ecfb3c099b 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -200,7 +200,7 @@ 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 [SEC] execute query every SEC seconds\n");
+ HELP0(" \\watch [[i=]SEC] [c=N] execute query every SEC seconds, up to N times\n");
HELP0("\n");
HELP0("Help\n");
diff --git a/src/bin/psql/t/001_basic.pl b/src/bin/psql/t/001_basic.pl
index 64ce012062..56b1e3e4a6 100644
--- a/src/bin/psql/t/001_basic.pl
+++ b/src/bin/psql/t/001_basic.pl
@@ -350,21 +350,38 @@ psql_like(
'\copy from with DEFAULT'
);
+# Check \watch
+psql_like(
+ $node,
+ 'SELECT 1 \watch c=3 i=0.01',
+ qr/1\n1\n1/,
+ '\watch with 3 iterations');
+
# Check \watch errors
psql_fails_like(
$node,
- 'SELECT 1;\watch -10',
- qr/incorrect interval value '-10'/,
+ 'SELECT 1 \watch -10',
+ qr/incorrect interval value "-10"/,
'\watch, negative interval');
psql_fails_like(
$node,
- 'SELECT 1;\watch 10ab',
- qr/incorrect interval value '10ab'/,
- '\watch incorrect interval');
+ 'SELECT 1 \watch 10ab',
+ qr/incorrect interval value "10ab"/,
+ '\watch, incorrect interval');
psql_fails_like(
$node,
- 'SELECT 1;\watch 10e400',
- qr/incorrect interval value '10e400'/,
- '\watch out-of-range interval');
+ 'SELECT 1 \watch 10e400',
+ qr/incorrect interval value "10e400"/,
+ '\watch, out-of-range interval');
+psql_fails_like(
+ $node,
+ 'SELECT 1 \watch 1 1',
+ qr/interval value is specified more than once/,
+ '\watch, interval value is specified more than once');
+psql_fails_like(
+ $node,
+ 'SELECT 1 \watch c=1 c=1',
+ qr/iteration count is specified more than once/,
+ '\watch, iteration count is specified more than once');
done_testing();
diff --git a/src/test/regress/expected/psql.out b/src/test/regress/expected/psql.out
index c00e28361c..956e475447 100644
--- a/src/test/regress/expected/psql.out
+++ b/src/test/regress/expected/psql.out
@@ -4536,7 +4536,7 @@ invalid command \lo
\timing arg1
\unset arg1
\w arg1
- \watch arg1
+ \watch arg1 arg2
\x arg1
-- \else here is eaten as part of OT_FILEPIPE argument
\w |/no/such/file \else
diff --git a/src/test/regress/sql/psql.sql b/src/test/regress/sql/psql.sql
index 961783d6ea..630f638f02 100644
--- a/src/test/regress/sql/psql.sql
+++ b/src/test/regress/sql/psql.sql
@@ -1022,7 +1022,7 @@ select \if false \\ (bogus \else \\ 42 \endif \\ forty_two;
\timing arg1
\unset arg1
\w arg1
- \watch arg1
+ \watch arg1 arg2
\x arg1
-- \else here is eaten as part of OT_FILEPIPE argument
\w |/no/such/file \else