pgbench - add option to show actual builtin script code

[Fabien COELHO]

Hello devs,
The minor attached patch $SUBJECT, so that it can be inspected easily, 
instead of having to look at the source code or whatever.

  sh> pgbench --list select-only
  -- select-only: <builtin: select only>
  \set aid random(1, 100000 * :scale)
  SELECT abalance FROM pgbench_accounts WHERE aid = :aid;

The builtin list output is also slightly improved:

  sh> pgbench -b list
  Available builtin scripts:
        tpcb-like: <builtin: TPC-B (sort of)>
    simple-update: <builtin: simple update>
      select-only: <builtin: select only>

--
Fabien.diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index ee2501be55..4b7368b05e 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -355,7 +355,6 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
       </listitem>
      </varlistentry>
 
-
      <varlistentry>
       <term><option>-c</option> <replaceable>clients</replaceable></term>
       <term><option>--client=</option><replaceable>clients</replaceable></term>
@@ -456,6 +455,16 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
        </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><option>--list</option><replaceable>scriptname</replaceable></term>
+      <listitem>
+       <para>
+        Show the actual code of builtin script <replaceable>scriptname</replaceable>
+        on stderr, and exit immediately.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-M</option> <replaceable>querymode</replaceable></term>
       <term><option>--protocol=</option><replaceable>querymode</replaceable></term>
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 99529de52a..9f085508d9 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -651,6 +651,7 @@ usage(void)
 		   "  --progress-timestamp     use Unix epoch timestamps for progress\n"
 		   "  --random-seed=SEED       set random seed (\"time\", \"rand\", integer)\n"
 		   "  --sampling-rate=NUM      fraction of transactions to log (e.g., 0.01 for 1%%)\n"
+		   "  --list=NAME              show builtin script code, then exit\n"
 		   "\nCommon options:\n"
 		   "  -d, --debug              print debugging output\n"
 		   "  -h, --host=HOSTNAME      database server host or socket directory\n"
@@ -4658,7 +4659,7 @@ listAvailableScripts(void)
 
 	fprintf(stderr, "Available builtin scripts:\n");
 	for (i = 0; i < lengthof(builtin_script); i++)
-		fprintf(stderr, "\t%s\n", builtin_script[i].name);
+		fprintf(stderr, "  %13s: %s\n", builtin_script[i].name, builtin_script[i].desc);
 	fprintf(stderr, "\n");
 }
 
@@ -5095,6 +5096,7 @@ main(int argc, char **argv)
 		{"log-prefix", required_argument, NULL, 7},
 		{"foreign-keys", no_argument, NULL, 8},
 		{"random-seed", required_argument, NULL, 9},
+		{"list", required_argument, NULL, 10},
 		{NULL, 0, NULL, 0}
 	};
 
@@ -5447,6 +5449,13 @@ main(int argc, char **argv)
 					exit(1);
 				}
 				break;
+			case 10:			/* list */
+				{
+					const BuiltinScript   *s = findBuiltin(optarg);
+					fprintf(stderr, "-- %s: %s\n%s\n", s->name, s->desc, s->script);
+					exit(0);
+				}
+				break;
 			default:
 				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
 				exit(1);
diff --git a/src/bin/pgbench/t/002_pgbench_no_server.pl b/src/bin/pgbench/t/002_pgbench_no_server.pl
index 69a6d03bb3..d9cf01233c 100644
--- a/src/bin/pgbench/t/002_pgbench_no_server.pl
+++ b/src/bin/pgbench/t/002_pgbench_no_server.pl
@@ -218,6 +218,15 @@ pgbench(
 	],
 	'pgbench builtin list');
 
+# builtin listing
+pgbench(
+	'--list se',
+	0,
+	[qr{^$}],
+	[ qr{select-only: }, qr{SELECT abalance FROM pgbench_accounts WHERE},
+	  qr{(?!UPDATE)}, qr{(?!INSERT)} ],
+	'pgbench builtin listing');
+
 my @script_tests = (
 
 	# name, err, { file => contents }