integration: log slow queries and check for them (#4554)

I couldn't get this to work cleanly with
`--log-queries-not-using-indexes` because a couple of queries show up
during integration test runs, seemingly because the tables involved are
small enough that the optimizer finds it faster to skip the index.

Some possible followups:
 - Allow list those queries, or
 - Preload the DB with a certain number of certificates before the start
   of testing.

docker-compose.yml

@@ -73,7 +73,12 @@ services:
               - boulder-mysql
         environment:
             MYSQL_ALLOW_EMPTY_PASSWORD: "yes"
-        command: mysqld --bind-address=0.0.0.0
+        # Send slow queries to a table so we can check for them in the
+        # integration tests. For now we ignore queries not using indexes,
+        # because that seems to trigger based on the optimizer's choice to not
+        # use an index for certain queries, particularly when tables are still
+        # small.
+        command: mysqld --bind-address=0.0.0.0 --slow-query-log --log-output=TABLE --log-queries-not-using-indexes=OFF
         logging:
             driver: none
     netaccess:

test/integration-test.py

@@ -308,9 +308,22 @@ def main():
     if not startservers.check():
         raise Exception("startservers.check failed")
 
+    check_slow_queries()
+
     global exit_status
     exit_status = 0
 
+def check_slow_queries():
+    """Checks that we haven't run any slow queries during the integration test.
+
+    This depends on flags set on mysqld in docker-compose.yml.
+    """
+    output = run("mysql -h boulder-mysql -D boulder_sa_integration -e " +
+        "'select * from mysql.slow_log where user_host not like \"test_setup%\" \G'")
+    if len(output) > 0:
+        print(output)
+        raise Exception("Found slow queries in the slow query log")
+
 def run_chisel(test_case_filter):
     for key, value in inspect.getmembers(v1_integration):
       if callable(value) and key.startswith('test_') and re.search(test_case_filter, key):