From b203630ec3e8e57d2dece0c76f1578377ecbc897 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Sun, 14 Jun 2020 23:26:58 +1200
Subject: [PATCH v5 3/3] Add test for SERIALIZABLE on streaming replicas.

This is a (slightly) distributed version of the isolation test in
src/test/isolation/read-only-anomaly-3.spec.
---
 src/test/recovery/t/021_serializable.pl | 107 ++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 src/test/recovery/t/021_serializable.pl

diff --git a/src/test/recovery/t/021_serializable.pl b/src/test/recovery/t/021_serializable.pl
new file mode 100644
index 0000000000..6ab20b8b42
--- /dev/null
+++ b/src/test/recovery/t/021_serializable.pl
@@ -0,0 +1,107 @@
+# Like src/test/isolation/specs/read-only-anomaly-3.spec, except that
+# s3 runs on a streaming replica server.
+
+use strict;
+use warnings;
+
+use PostgresNode;
+use PsqlSession;
+use TestLib;
+use Test::More tests => 13;
+
+my $node_primary = get_new_node('primary');
+$node_primary->init(allows_streaming => 1);
+$node_primary->start;
+
+$node_primary->safe_psql('postgres',
+	"CREATE TABLE bank_account (id TEXT PRIMARY KEY, balance DECIMAL NOT NULL)");
+$node_primary->safe_psql('postgres',
+	"INSERT INTO bank_account (id, balance) VALUES ('X', 0), ('Y', 0)");
+
+my $backup_name = 'my_backup';
+$node_primary->backup($backup_name);
+
+my $node_replica = get_new_node('replica');
+$node_replica->init_from_backup($node_primary, $backup_name,
+	has_streaming => 1);
+$node_replica->start;
+
+# We need three sessions.  s1 and s2 are on the primary, s3 is on the replica.
+my $s1 = PsqlSession->new($node_primary, "postgres");
+$s1->send("\\set PROMPT1 ''\n", 2);
+$s1->send("\\set PROMPT2 ''\n", 1);
+my $s2 = PsqlSession->new($node_primary, "postgres");
+$s2->send("\\set PROMPT1 ''\n", 2);
+$s2->send("\\set PROMPT2 ''\n", 1);
+my $s3 = PsqlSession->new($node_replica, "postgres");
+$s3->send("\\set PROMPT1 ''\n", 2);
+$s3->send("\\set PROMPT2 ''\n", 1);
+
+my @lines;
+my $result;
+@lines = $s1->send("BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;\n", 2);
+shift @lines;
+is(shift @lines, "BEGIN");
+@lines = $s2->send("BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;\n", 2);
+shift @lines;
+is(shift @lines, "BEGIN");
+@lines = $s3->send("BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;\n", 2);
+shift @lines;
+is(shift @lines, "BEGIN");
+
+# s2rx
+@lines = $s2->send("SELECT balance FROM bank_account WHERE id = 'X';\n", 2);
+shift @lines;
+is(shift @lines, "0");
+
+# s2ry
+@lines = $s2->send("SELECT balance FROM bank_account WHERE id = 'Y';\n", 2);
+shift @lines;
+is(shift @lines, "0");
+
+# s1ry
+@lines = $s1->send("SELECT balance FROM bank_account WHERE id = 'Y';\n", 2);
+shift @lines;
+is(shift @lines, "0");
+
+# s1wy
+@lines = $s1->send("UPDATE bank_account SET balance = 20 WHERE id = 'Y';\n", 2);
+shift @lines;
+is(shift @lines, "UPDATE 1");
+
+# s1c
+@lines = $s1->send("COMMIT;\n", 2);
+shift @lines;
+is(shift @lines, "COMMIT");
+
+# now, we want to wait until the replica has replayed s1c
+my $until_lsn =
+  $node_primary->safe_psql('postgres', "SELECT pg_current_wal_lsn()");
+$node_replica->poll_query_until('postgres',
+    "SELECT (pg_last_wal_replay_lsn() - '$until_lsn'::pg_lsn) >= 0")
+  or die "standby never caught up";
+
+# s3r begins...
+@lines = $s3->send("SELECT id, balance FROM bank_account WHERE id IN ('X', 'Y') ORDER BY id;\n", 1);
+$s3->check_is_blocked();
+
+# s2wx
+@lines = $s2->send("UPDATE bank_account SET balance = -11 WHERE id = 'X';\n", 2);
+shift @lines;
+is(shift @lines, "UPDATE 1");
+
+# s2c
+@lines = $s2->send("COMMIT;\n", 2);
+shift @lines;
+is(shift @lines, "COMMIT");
+
+# ... s3r completes
+@lines = $s3->send("", 2);
+is(shift @lines, "X|-11");
+is(shift @lines, "Y|20");
+
+# s3c
+@lines = $s3->send("COMMIT;\n", 2);
+shift @lines;
+is(shift @lines, "COMMIT");
+
-- 
2.20.1