[autotest] Fix db_optimize.

Took less than 2 minutes on x86-mario shard with over 3 months
history, ~80,000 rows in afe_jobs ~110,000 rows in
afe_special_tasks.

TEST=Run the script
BUG=chromium:455486

Change-Id: I0feb16e2da608e2db5194907be5d789dcf099fde
Reviewed-on: https://chromium-review.googlesource.com/259232
Tested-by: Fang Deng <[email protected]>
Reviewed-by: Mungyung Ryu <[email protected]>
Commit-Queue: Fang Deng <[email protected]>
diff --git a/contrib/db_optimize.py b/contrib/db_optimize.py
index 830999f..8ade192 100755
--- a/contrib/db_optimize.py
+++ b/contrib/db_optimize.py
@@ -10,21 +10,24 @@
 systems.
 """
 
+import logging
 import socket
 import subprocess
+import sys
 
 import common
 from autotest_lib.client.common_lib.cros.graphite import autotest_stats
 from autotest_lib.frontend import database_settings_helper
 from autotest_lib.scheduler import email_manager
 
-
+# Format Appears as: [Date] [Time] - [Msg Level] - [Message]
+LOGGING_FORMAT = '%(asctime)s - %(levelname)s - %(message)s'
 STATS_KEY = 'db_optimize.%s' % socket.gethostname()
 timer = autotest_stats.Timer(STATS_KEY)
 
 @timer.decorate
 def main_without_exception_handling():
-    database_settings = database_settings_helper.get_database_config()
+    database_settings = database_settings_helper.get_default_db_config()
     command = ['mysqlcheck',
                '-o', database_settings['NAME'],
                '-u', database_settings['USER'],
@@ -34,6 +37,8 @@
 
 
 def main():
+    logging.basicConfig(level=logging.INFO, format=LOGGING_FORMAT)
+    logging.info('Calling: %s', sys.argv)
     try:
         main_without_exception_handling()
     except Exception as e:
@@ -43,6 +48,7 @@
         raise
     finally:
         email_manager.manager.send_queued_emails()
+    logging.info('db_optimize completed.')
 
 
 if __name__ == '__main__':