Disable should_process_waiting_queue_as_fifo test
COUCHDB-3140
This PR disables the problematic queue-as-fifo test. As written, any
call in a test to spawn_client/1 returns immediately, and does not
guarantee that the call to couch_query_servers:get_ddoc_process/2
returns before control flow proceeds to the next line in the eunit test.
As it turns out, on Windows, the call to spawn_client for ddoc5 succeeds
prior to the ddoc4 call in this test, thus always failing.
Insertion of a timer:sleep/1 call between the spawn_client/1 calls seems
to solve the problem, but even this is "lucky" behaviour. Semantically
the way this test is written, with spawn_client/1 using spawn/1 to spin
off the actual get_ddoc_process/2 call, there is no guarantee that the
couch_proc_manager FIFO queue is being populated correctly.
Further, if the get_ddoc_process/2 call takes longer than the defined
timeout (5000 ms) this test will always fail, as no provision is made to
keep trying for an os_process after that time. Again we are "lucky" that
the test runs fast enough that this is not a problem, but relying on a
performant BEAM VM for test success in any regard is equally
problematic.
For this reason I am completely commenting out this test until the
harness can be fixed. I believe the impact to couchdb is minimal.
(It also suggests we may want to rethink how requests for os processes
are queued and issued at some point in the future; this approach seems
sub-optimal, especially if strict FIFO ordering is an expectation of the
system.)
/cc @eiri @rnewson @janl
diff --git a/test/couchdb_os_proc_pool.erl b/test/couchdb_os_proc_pool.erl
index 54d19f0..f14af68 100644
--- a/test/couchdb_os_proc_pool.erl
+++ b/test/couchdb_os_proc_pool.erl
@@ -38,7 +38,7 @@
should_block_new_proc_on_full_pool(),
should_free_slot_on_proc_unexpected_exit(),
should_reuse_known_proc(),
- should_process_waiting_queue_as_fifo(),
+% should_process_waiting_queue_as_fifo(),
should_reduce_pool_on_idle_os_procs()
]
}
@@ -148,34 +148,35 @@
end).
-should_process_waiting_queue_as_fifo() ->
- ?_test(begin
- Client1 = spawn_client(<<"ddoc1">>),
- Client2 = spawn_client(<<"ddoc2">>),
- Client3 = spawn_client(<<"ddoc3">>),
- Client4 = spawn_client(<<"ddoc4">>),
- Client5 = spawn_client(<<"ddoc5">>),
-
- ?assertEqual(ok, ping_client(Client1)),
- ?assertEqual(ok, ping_client(Client2)),
- ?assertEqual(ok, ping_client(Client3)),
- ?assertEqual(timeout, ping_client(Client4)),
- ?assertEqual(timeout, ping_client(Client5)),
-
- Proc1 = get_client_proc(Client1, "1"),
- ?assertEqual(ok, stop_client(Client1)),
- ?assertEqual(ok, ping_client(Client4)),
- Proc4 = get_client_proc(Client4, "4"),
-
- ?assertNotEqual(Proc4#proc.client, Proc1#proc.client),
- ?assertEqual(Proc1#proc.pid, Proc4#proc.pid),
- ?assertEqual(timeout, ping_client(Client5)),
-
- ?assertEqual(ok, stop_client(Client2)),
- ?assertEqual(ok, stop_client(Client3)),
- ?assertEqual(ok, stop_client(Client4)),
- ?assertEqual(ok, stop_client(Client5))
- end).
+%should_process_waiting_queue_as_fifo() ->
+% ?_test(begin
+% Client1 = spawn_client(<<"ddoc1">>),
+% Client2 = spawn_client(<<"ddoc2">>),
+% Client3 = spawn_client(<<"ddoc3">>),
+% Client4 = spawn_client(<<"ddoc4">>),
+% timer:sleep(100),
+% Client5 = spawn_client(<<"ddoc5">>),
+%
+% ?assertEqual(ok, ping_client(Client1)),
+% ?assertEqual(ok, ping_client(Client2)),
+% ?assertEqual(ok, ping_client(Client3)),
+% ?assertEqual(timeout, ping_client(Client4)),
+% ?assertEqual(timeout, ping_client(Client5)),
+%
+% Proc1 = get_client_proc(Client1, "1"),
+% ?assertEqual(ok, stop_client(Client1)),
+% ?assertEqual(ok, ping_client(Client4)),
+% Proc4 = get_client_proc(Client4, "4"),
+%
+% ?assertNotEqual(Proc4#proc.client, Proc1#proc.client),
+% ?assertEqual(Proc1#proc.pid, Proc4#proc.pid),
+% ?assertEqual(timeout, ping_client(Client5)),
+%
+% ?assertEqual(ok, stop_client(Client2)),
+% ?assertEqual(ok, stop_client(Client3)),
+% ?assertEqual(ok, stop_client(Client4)),
+% ?assertEqual(ok, stop_client(Client5))
+% end).
should_reduce_pool_on_idle_os_procs() ->
