pgbench: add --partitions and --partition-method options.

These new options allow users to partition the pgbench_accounts table by
specifying the number of partitions and partitioning method.  The values
allowed for partitioning method are range and hash.

This feature allows users to measure the overhead of partitioning if any.

Author: Fabien COELHO
Reviewed-by: Amit Kapila, Amit Langote, Dilip Kumar, Asif Rehman, and
Alvaro Herrera
Discussion: https://postgr.es/m/alpine.DEB.2.21.1907230826190.7008@lancre

doc/src/sgml/ref/pgbench.sgml

@@ -306,6 +306,31 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
       </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><option>--partitions=<replaceable>NUM</replaceable></option></term>
+      <listitem>
+       <para>
+        Create a partitioned <literal>pgbench_accounts</literal> table with
+        <replaceable>NUM</replaceable> partitions of nearly equal size for
+        the scaled number of accounts.
+        Default is <literal>0</literal>, meaning no partitioning.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>--partition-method=<replaceable>NAME</replaceable></option></term>
+      <listitem>
+       <para>
+        Create a partitioned <literal>pgbench_accounts</literal> table with
+        <replaceable>NAME</replaceable> method.
+        Expected values are <literal>range</literal> or <literal>hash</literal>.
+        This option requires that <option>--partitions</option> is set to non-zero.
+        If unspecified, default is <literal>range</literal>.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>--tablespace=<replaceable>tablespace</replaceable></option></term>
       <listitem>

src/bin/pgbench/t/001_pgbench_with_server.pl

@@ -58,6 +58,19 @@ sub pgbench
 	return;
 }
 
+# tablespace for testing, because partitioned tables cannot use pg_default
+# explicitly and we want to test that table creation with tablespace works
+# for partitioned tables.
+my $ts = $node->basedir . '/regress_pgbench_tap_1_ts_dir';
+mkdir $ts or die "cannot create directory $ts";
+# this takes care of WIN-specific path issues
+my $ets = TestLib::perl2host($ts);
+
+# the next commands will issue a syntax error if the path contains a "'"
+$node->safe_psql('postgres',
+       "CREATE TABLESPACE regress_pgbench_tap_1_ts LOCATION '$ets';"
+);
+
 # Test concurrent OID generation via pg_enum_oid_index.  This indirectly
 # exercises LWLock and spinlock concurrency.
 my $labels = join ',', map { "'l$_'" } 1 .. 1000;
@@ -100,12 +113,13 @@ pgbench(
 
 # Again, with all possible options
 pgbench(
-	'--initialize --init-steps=dtpvg --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=pg_default --index-tablespace=pg_default',
+	'--initialize --init-steps=dtpvg --scale=1 --unlogged-tables --fillfactor=98 --foreign-keys --quiet --tablespace=regress_pgbench_tap_1_ts --index-tablespace=regress_pgbench_tap_1_ts --partitions=2 --partition-method=hash',
 	0,
 	[qr{^$}i],
 	[
 		qr{dropping old tables},
 		qr{creating tables},
+		qr{creating 2 partitions},
 		qr{vacuuming},
 		qr{creating primary keys},
 		qr{creating foreign keys},
@@ -116,12 +130,13 @@ pgbench(
 
 # Test interaction of --init-steps with legacy step-selection options
 pgbench(
-	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables',
+	'--initialize --init-steps=dtpvgvv --no-vacuum --foreign-keys --unlogged-tables --partitions=3',
 	0,
 	[qr{^$}],
 	[
 		qr{dropping old tables},
 		qr{creating tables},
+		qr{creating 3 partitions},
 		qr{creating primary keys},
 		qr{.* of .* tuples \(.*\) done},
 		qr{creating foreign keys},
@@ -910,5 +925,6 @@ check_pgbench_logs($bdir, '001_pgbench_log_3', 1, 10, 10,
 	qr{^\d \d{1,2} \d+ \d \d+ \d+$});
 
 # done
+$node->safe_psql('postgres', 'DROP TABLESPACE regress_pgbench_tap_1_ts');
 $node->stop;
 done_testing();

src/bin/pgbench/t/002_pgbench_no_server.pl

@@ -157,6 +157,13 @@ my @options = (
 			qr{error while setting random seed from --random-seed option}
 		]
 	],
+	[ 'bad partition type', '-i --partition-method=BAD', [qr{"range"}, qr{"hash"}, qr{"BAD"}] ],
+	[ 'bad partition number', '-i --partitions -1', [ qr{invalid number of partitions: "-1"} ] ],
+	[
+		'partition method without partitioning',
+		'-i --partition-method=hash',
+		[ qr{partition-method requires greater than zero --partitions} ]
+	],
 
 	# logging sub-options
 	[