1 files changed, 48 insertions, 0 deletions
diff --git a/src/test/isolation/specs/read-write-unique-4.spec b/src/test/isolation/specs/read-write-unique-4.spec
new file mode 100644
index 00000000000..ec447823484
--- /dev/null
+++ b/src/test/isolation/specs/read-write-unique-4.spec
@@ -0,0 +1,48 @@
+# Read-write-unique test.
+# Implementing a gapless sequence of ID numbers for each year.
+
+setup
+{
+  CREATE TABLE invoice (
+    year int,
+    invoice_number int,
+    PRIMARY KEY (year, invoice_number)
+  );
+
+  INSERT INTO invoice VALUES (2016, 1), (2016, 2);
+}
+
+teardown
+{
+  DROP TABLE invoice;
+}
+
+session "s1"
+setup { BEGIN ISOLATION LEVEL SERIALIZABLE; }
+step "r1" { SELECT COALESCE(MAX(invoice_number) + 1, 1) FROM invoice WHERE year = 2016; }
+step "w1" { INSERT INTO invoice VALUES (2016, 3); }
+step "c1" { COMMIT; }
+
+session "s2"
+setup { BEGIN ISOLATION LEVEL SERIALIZABLE; }
+step "r2" { SELECT COALESCE(MAX(invoice_number) + 1, 1) FROM invoice WHERE year = 2016; }
+step "w2" { INSERT INTO invoice VALUES (2016, 3); }
+step "c2" { COMMIT; }
+
+# if they both read first then there should be an SSI conflict
+permutation "r1" "r2" "w1" "w2" "c1" "c2"
+
+# cases where one session doesn't explicitly read before writing:
+
+# if s2 doesn't explicitly read, then trying to insert the value
+# generates a unique constraint violation after s1 commits, as if s2
+# ran after s1
+permutation "r1" "w1" "w2" "c1" "c2"
+
+# if s1 doesn't explicitly read, but s2 does, then s1 inserts and
+# commits first, should s2 experience an SSI failure instead of a
+# unique constraint violation?  there is no serial order of operations
+# (s1, s2) or (s2, s1) where s1 succeeds, and s2 doesn't see the row
+# in an explicit select but then fails to insert due to unique
+# constraint violation
+permutation "r2" "w1" "w2" "c1" "c2"