Add an SSI regression test that tests all interesting permutations in the

order of begin, prepare, and commit of three concurrent transactions that
have conflicts between them.

The test runs for a quite long time, and the expected output file is huge,
but this test caught some serious bugs during development, so seems
worthwhile to keep. The test uses prepared transactions, so it fails if the
server has max_prepared_transactions=0. Because of that, it's marked as
"ignore" in the schedule file.

Dan Ports

src/test/isolation/isolation_schedule

@@ -9,6 +9,11 @@ test: ri-trigger
 test: partial-index
 test: two-ids
 test: multiple-row-versions
+# Ignore failure from prepared-transactions test, because it fails if
+# prepared transactions are disabled in the server. It should pass if they're
+# enabled, however.
+ignore: prepared-transactions
+test: prepared-transactions
 test: fk-contention
 test: fk-deadlock
 test: fk-deadlock2

src/test/isolation/isolationtester.c

@@ -416,7 +416,11 @@ run_permutation(TestSpec * testspec, int nsteps, Step ** steps)
 		if (testspec->sessions[i]->setupsql)
 		{
 			res = PQexec(conns[i + 1], testspec->sessions[i]->setupsql);
-			if (PQresultStatus(res) != PGRES_COMMAND_OK)
+			if (PQresultStatus(res) == PGRES_TUPLES_OK)
+			{
+				printResultSet(res);
+			}
+			else if (PQresultStatus(res) != PGRES_COMMAND_OK)
 			{
 				fprintf(stderr, "setup of session %s failed: %s",
 						testspec->sessions[i]->name,
@@ -477,7 +481,11 @@ run_permutation(TestSpec * testspec, int nsteps, Step ** steps)
 	if (testspec->teardownsql)
 	{
 		res = PQexec(conns[0], testspec->teardownsql);
-		if (PQresultStatus(res) != PGRES_COMMAND_OK)
+		if (PQresultStatus(res) == PGRES_TUPLES_OK)
+		{
+			printResultSet(res);
+		}
+		else if (PQresultStatus(res) != PGRES_COMMAND_OK)
 		{
 			fprintf(stderr, "teardown failed: %s",
 					PQerrorMessage(conns[0]));