Add some isolation tests for deadlock detection and resolution.

Previously, we had no test coverage for the deadlock detector.

src/test/isolation/expected/deadlock-hard.out

+Parsed test spec with 8 sessions
+
+starting permutation: s1a1 s2a2 s3a3 s4a4 s5a5 s6a6 s7a7 s8a8 s1a2 s2a3 s3a4 s4a5 s5a6 s6a7 s7a8 s8a1 s8c s7c s6c s5c s4c s3c s2c s1c
+step s1a1: LOCK TABLE a1;
+step s2a2: LOCK TABLE a2;
+step s3a3: LOCK TABLE a3;
+step s4a4: LOCK TABLE a4;
+step s5a5: LOCK TABLE a5;
+step s6a6: LOCK TABLE a6;
+step s7a7: LOCK TABLE a7;
+step s8a8: LOCK TABLE a8;
+step s1a2: LOCK TABLE a2; <waiting ...>
+step s2a3: LOCK TABLE a3; <waiting ...>
+step s3a4: LOCK TABLE a4; <waiting ...>
+step s4a5: LOCK TABLE a5; <waiting ...>
+step s5a6: LOCK TABLE a6; <waiting ...>
+step s6a7: LOCK TABLE a7; <waiting ...>
+step s7a8: LOCK TABLE a8; <waiting ...>
+step s8a1: LOCK TABLE a1;
+step s7a8: <... completed>
+error in steps s8a1 s7a8: ERROR:  deadlock detected
+step s8c: COMMIT;
+step s7c: COMMIT;
+step s6a7: <... completed>
+step s6c: COMMIT;
+step s5a6: <... completed>
+step s5c: COMMIT;
+step s4a5: <... completed>
+step s4c: COMMIT;
+step s3a4: <... completed>
+step s3c: COMMIT;
+step s2a3: <... completed>
+step s2c: COMMIT;
+step s1a2: <... completed>
+step s1c: COMMIT;

src/test/isolation/expected/deadlock-simple.out

+Parsed test spec with 2 sessions
+
+starting permutation: s1as s2as s1ae s2ae s1c s2c
+step s1as: LOCK TABLE a1 IN ACCESS SHARE MODE;
+step s2as: LOCK TABLE a1 IN ACCESS SHARE MODE;
+step s1ae: LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE; <waiting ...>
+step s2ae: LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE;
+step s1ae: <... completed>
+error in steps s2ae s1ae: ERROR:  deadlock detected
+step s1c: COMMIT;
+step s2c: COMMIT;

src/test/isolation/expected/deadlock-soft-2.out

+Parsed test spec with 4 sessions
+
+starting permutation: s1a s2a s2b s3a s4a s1b s1c s2c s3c s4c
+step s1a: LOCK TABLE a1 IN SHARE UPDATE EXCLUSIVE MODE;
+step s2a: LOCK TABLE a2 IN ACCESS SHARE MODE;
+step s2b: LOCK TABLE a1 IN SHARE UPDATE EXCLUSIVE MODE; <waiting ...>
+step s3a: LOCK TABLE a2 IN ACCESS EXCLUSIVE MODE; <waiting ...>
+step s4a: LOCK TABLE a2 IN ACCESS EXCLUSIVE MODE; <waiting ...>
+step s1b: LOCK TABLE a2 IN SHARE UPDATE EXCLUSIVE MODE; <waiting ...>
+step s1b: <... completed>
+step s1c: COMMIT;
+step s2b: <... completed>
+step s2c: COMMIT;
+step s3a: <... completed>
+step s3c: COMMIT;
+step s4a: <... completed>
+step s4c: COMMIT;

src/test/isolation/expected/deadlock-soft.out

+Parsed test spec with 4 sessions
+
+starting permutation: d1a1 d2a2 e1l e2l d1a2 d2a1 d1c e1c d2c e2c
+step d1a1: LOCK TABLE a1 IN ACCESS SHARE MODE;
+step d2a2: LOCK TABLE a2 IN ACCESS SHARE MODE;
+step e1l: LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE; <waiting ...>
+step e2l: LOCK TABLE a2 IN ACCESS EXCLUSIVE MODE; <waiting ...>
+step d1a2: LOCK TABLE a2 IN ACCESS SHARE MODE; <waiting ...>
+step d2a1: LOCK TABLE a1 IN ACCESS SHARE MODE; <waiting ...>
+step d1a2: <... completed>
+step d1c: COMMIT;
+step e1l: <... completed>
+step e1c: COMMIT;
+step d2a1: <... completed>
+step d2c: COMMIT;
+step e2l: <... completed>
+step e2c: COMMIT;

src/test/isolation/isolation_schedule

@@ -10,6 +10,10 @@ test: partial-index
 test: two-ids
 test: multiple-row-versions
 test: index-only-scan
+test: deadlock-simple
+test: deadlock-hard
+test: deadlock-soft
+test: deadlock-soft-2
 test: fk-contention
 test: fk-deadlock
 test: fk-deadlock2

src/test/isolation/specs/deadlock-hard.spec

+# This is a straightforward deadlock scenario.  Since it involves more than
+# two processes, the mainlock detector will find the problem and rollback the
+# backend which discovers it.
+
+setup
+{
+  CREATE TABLE a1 ();
+  CREATE TABLE a2 ();
+  CREATE TABLE a3 ();
+  CREATE TABLE a4 ();
+  CREATE TABLE a5 ();
+  CREATE TABLE a6 ();
+  CREATE TABLE a7 ();
+  CREATE TABLE a8 ();
+}
+
+teardown
+{
+  DROP TABLE a1, a2, a3, a4, a5, a6, a7, a8;
+}
+
+session "s1"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "s1a1"	{ LOCK TABLE a1; }
+step "s1a2"	{ LOCK TABLE a2; }
+step "s1c"	{ COMMIT; }
+
+session "s2"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "s2a2"	{ LOCK TABLE a2; }
+step "s2a3"	{ LOCK TABLE a3; }
+step "s2c"	{ COMMIT; }
+
+session "s3"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "s3a3"	{ LOCK TABLE a3; }
+step "s3a4"	{ LOCK TABLE a4; }
+step "s3c"	{ COMMIT; }
+
+session "s4"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "s4a4"	{ LOCK TABLE a4; }
+step "s4a5"	{ LOCK TABLE a5; }
+step "s4c"	{ COMMIT; }
+
+session "s5"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "s5a5"	{ LOCK TABLE a5; }
+step "s5a6"	{ LOCK TABLE a6; }
+step "s5c"	{ COMMIT; }
+
+session "s6"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "s6a6"	{ LOCK TABLE a6; }
+step "s6a7"	{ LOCK TABLE a7; }
+step "s6c"	{ COMMIT; }
+
+session "s7"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "s7a7"	{ LOCK TABLE a7; }
+step "s7a8"	{ LOCK TABLE a8; }
+step "s7c"	{ COMMIT; }
+
+session "s8"
+setup		{ BEGIN; SET deadlock_timeout = '10ms'; }
+step "s8a8"	{ LOCK TABLE a8; }
+step "s8a1"	{ LOCK TABLE a1; }
+step "s8c"	{ COMMIT; }
+
+permutation "s1a1" "s2a2" "s3a3" "s4a4" "s5a5" "s6a6" "s7a7" "s8a8" "s1a2" "s2a3" "s3a4" "s4a5" "s5a6" "s6a7" "s7a8" "s8a1" "s8c" "s7c" "s6c" "s5c" "s4c" "s3c" "s2c" "s1c"

src/test/isolation/specs/deadlock-simple.spec

+# The deadlock detector has a special case for "simple" deadlocks.  A simple
+# deadlock occurs when we attempt a lock upgrade while another process waits
+# for a lock upgrade on the same object; and the sought locks conflict with
+# those already held, so that neither process can complete its upgrade until
+# the other releases locks.  Test this scenario.
+
+setup
+{
+  CREATE TABLE a1 ();
+}
+
+teardown
+{
+  DROP TABLE a1;
+}
+
+session "s1"
+setup		{ BEGIN; }
+step "s1as"	{ LOCK TABLE a1 IN ACCESS SHARE MODE; }
+step "s1ae"	{ LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE; }
+step "s1c"	{ COMMIT; }
+
+session "s2"
+setup		{ BEGIN; }
+step "s2as"	{ LOCK TABLE a1 IN ACCESS SHARE MODE; }
+step "s2ae"	{ LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE; }
+step "s2c"	{ COMMIT; }
+
+permutation "s1as" "s2as" "s1ae" "s2ae" "s1c" "s2c"

src/test/isolation/specs/deadlock-soft-2.spec

+# Soft deadlock requiring reversal of multiple wait-edges.  s1 must
+# jump over both s3 and s4 and acquire the lock on a2 immediately,
+# since s3 and s4 are hard-blocked on a1.
+
+setup
+{
+  CREATE TABLE a1 ();
+  CREATE TABLE a2 ();
+}
+
+teardown
+{
+  DROP TABLE a1, a2;
+}
+
+session "s1"
+setup		{ BEGIN; }
+step "s1a"	{ LOCK TABLE a1 IN SHARE UPDATE EXCLUSIVE MODE; }
+step "s1b"	{ LOCK TABLE a2 IN SHARE UPDATE EXCLUSIVE MODE; }
+step "s1c"	{ COMMIT; }
+
+session "s2"
+setup		{ BEGIN; }
+step "s2a" 	{ LOCK TABLE a2 IN ACCESS SHARE MODE; }
+step "s2b" 	{ LOCK TABLE a1 IN SHARE UPDATE EXCLUSIVE MODE; }
+step "s2c"	{ COMMIT; }
+
+session "s3"
+setup		{ BEGIN; }
+step "s3a"	{ LOCK TABLE a2 IN ACCESS EXCLUSIVE MODE; }
+step "s3c"	{ COMMIT; }
+
+session "s4"
+setup		{ BEGIN; }
+step "s4a"	{ LOCK TABLE a2 IN ACCESS EXCLUSIVE MODE; }
+step "s4c"	{ COMMIT; }
+
+permutation "s1a" "s2a" "s2b" "s3a" "s4a" "s1b" "s1c" "s2c" "s3c" "s4c"

src/test/isolation/specs/deadlock-soft.spec

+# Four-process deadlock with two hard edges and two soft edges.
+# d2 waits for e1 (soft edge), e1 waits for d1 (hard edge),
+# d1 waits for e2 (soft edge), e2 waits for d2 (hard edge).
+# The deadlock detector resolves the deadlock by reversing the d1-e2 edge,
+# unblocking d1.
+
+setup
+{
+  CREATE TABLE a1 ();
+  CREATE TABLE a2 ();
+}
+
+teardown
+{
+  DROP TABLE a1, a2;
+}
+
+session "d1"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "d1a1"	{ LOCK TABLE a1 IN ACCESS SHARE MODE; }
+step "d1a2"	{ LOCK TABLE a2 IN ACCESS SHARE MODE; }
+step "d1c"	{ COMMIT; }
+
+session "d2"
+setup		{ BEGIN; SET deadlock_timeout = '10ms'; }
+step "d2a2"	{ LOCK TABLE a2 IN ACCESS SHARE MODE; }
+step "d2a1"	{ LOCK TABLE a1 IN ACCESS SHARE MODE; }
+step "d2c"	{ COMMIT; }
+
+session "e1"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "e1l"	{ LOCK TABLE a1 IN ACCESS EXCLUSIVE MODE; }
+step "e1c"	{ COMMIT; }
+
+session "e2"
+setup		{ BEGIN; SET deadlock_timeout = '10s'; }
+step "e2l"	{ LOCK TABLE a2 IN ACCESS EXCLUSIVE MODE; }
+step "e2c"	{ COMMIT; }
+
+permutation "d1a1" "d2a2" "e1l" "e2l" "d1a2" "d2a1" "d1c" "e1c" "d2c" "e2c"