Monitoring OAQ using mgw_gateway gives an odd result?

Question

When we submit the following query:
select  AGENT_STATUS, AGENT_PING, LAST_ERROR_DATE, LAST_ERROR_TIME from mgw_gateway;
We get this result:
SQL> select AGENT_STATUS, AGENT_PING, LAST_ERROR_DATE, LAST_ERROR_TIME from mgw_gateway;
MESSAGING GATEWAY IS NOT ONLINE
AGENT_STATUS         AGENT_PING           LAST_ERROR_DATE     LAST_ERR
RUNNING              UNREACHABLE
SQL> /
MESSAGING GATEWAY IS NOT ONLINE
AGENT_STATUS         AGENT_PING           LAST_ERROR_DATE     LAST_ERR
RUNNING              REACHABLE
SQL>
Those two queries were submitted sequentially.
DB is located on a Redhat Linux server, where we also submit these queries, so there should be no network issues.
The questions are:
Why is AGENT_PING showing two different results?
Why do we get "MESSAGING GATEWAY IS NOT ONLINE" no matter what the status?
We are up and running, data is being retrieved from MQ into the AQ queue tables, we are processing and not losing any data.
The "NOT ONLINE" message is not listed in any docs or online sources I have been able to find.
We are at a loss. How can we diagnose this?

Answer 1

Hi WoG, thanks for the reply.
No, not an "own" view, definitely sys.
Yes, your observation is correct. That "NOT ONLINE" message is separate from the select results and is not a column on the view.
Oracle version is:
     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
     With the Partitioning option
OS:
     Red Hat Enterprise Linux Server release 5.10 (Tikanga)
View definition as pulled via sqldeveloper:
CREATE OR REPLACE FORCE VIEW "SYS"."MGW_GATEWAY" ("AGENT_STATUS", "AGENT_PING",
  "AGENT_JOB", "AGENT_USER", "AGENT_DATABASE", "LAST_ERROR_DATE",
  "LAST_ERROR_TIME", "LAST_ERROR_MSG", "MAX_CONNECTIONS", "MAX_MEMORY",
  "MAX_THREADS", "AGENT_INSTANCE", "AGENT_START_TIME", "CONNTYPE", "AGENT_NAME"
  , "SERVICE", "INITFILE", "COMMENTS")
AS
  SELECT
    -- agent status
    CASE
      WHEN gw.agent_status = 0
      THEN 'NOT_STARTED'
      WHEN gw.agent_status = 1
      THEN 'START_SCHEDULED'
      WHEN gw.agent_status = 2
      THEN 'STARTING'
      WHEN gw.agent_status = 3
      THEN 'INITIALIZING'
      WHEN gw.agent_status = 4
      THEN 'RUNNING'
      WHEN gw.agent_status = 5
      THEN 'SHUTTING_DOWN'
      WHEN gw.agent_status = 6
      THEN 'BROKEN'
    END AGENT_STATUS,
    -- agent ping status; no ping (delay) if agent not yet started
    CASE
      WHEN gw.agent_status >= 0
      AND gw.agent_status  <=1
      THEN ''
      WHEN mgwi_admin.ping(gw.agent_name,3) = 1
      THEN 'REACHABLE'
      ELSE 'UNREACHABLE'
    END AGENT_PING,
    -- queued job used to start gateway agent
    gw.agent_job AGENT_JOB,
    -- agent user and database (connect string)
    gw.agent_user AGENT_USER,
    gw.agent_database AGENT_DATABASE,
    -- info about last gateway agent error
    gw.error_time LAST_ERROR_DATE,
    SUBSTR(TO_CHAR(gw.error_time, 'HH24:MI:SS'), 1, 8) LAST_ERROR_TIME,
    gw.error_message LAST_ERROR_MSG,
    -- misc config information
    gw.max_connections MAX_CONNECTIONS,
    gw.max_memory MAX_MEMORY,
    gw.max_threads MAX_THREADS,
    gw.agent_instance AGENT_INSTANCE,
    gw.agent_start_time AGENT_START_TIME,
    DECODE(bitand(gw.flags, 1), 0, 'JDBC_OCI', 1, 'JDBC_THIN', NULL) CONNTYPE,
    gw.agent_name AGENT_NAME,
    gw.service SERVICE,
    gw.initfile INITFILE,
    gw.comments COMMENTS
  FROM
    mgw$_gateway gw
WITH READ ONLY;
COMMENT ON TABLE "SYS"."MGW_GATEWAY"
IS
  'Messaging Gateway status and configuration information';