ERROR: RT Server denied access

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Problem:

ERROR: RT Server denied access

Resolution:

Information in this Brief applies to:

  • StarTeam MPX Server 5.1
  • Windows

Problem

The StarbaseMPX Event Transmitter broadcasts events by connecting a StarbaseMessage Broker and publishing messages. To guarantee that no other EventTransmitter is attempting to send messages for the same Starbase serverconfiguration, it sets an option called a "unique subject".Specifically, it sets this option to ""where is the Global Unique Identifier specific to theconfiguration. The Message Broker ensures that each unique subject is used byonly one process within the MPX cloud.

Normal network and process interruptions can cause the TCP/IP connectionbetween the Event Transmitter and Message Broker to be broken. When this occurs,the Event Transmitter periodically attempts to reconnect to the Message Broker.(During this period, StarTeam clients also detect that the Event Transmitter is"offline" and switch to non-MPX mode.) Normally, the connection isreestablished, and StarTeam clients revert back to MPX mode.

Under certain conditions, however, a Message Broker may not detect that aTCP/IP connection has been lost. This occurs for "pure publisher"applications such as the Event Transmitter, to which the Message Broker does notnormally send messages. When the Message Broker fails to detect a broken EventTransmitter connection, the entire MPX cloud will maintain state indicating thatthe Event Transmitter"s unique subject is still in use. Consequently, when theEvent Transmitter attempts to reconnect and use the same unique subject, theMessage Broker rejects it as not unique.

Workaround

In the StarTeam 5.2 release, this problem will be addressed by an enhancementto the underlying SmartSockets code, which will allow the Message Broker to sendperiodic "ping" messages through its connections. Consequently, if aconnection is lost, the Message Broker will detect it, delete the associatedunique subject state, and therefore allow a reconnect with the same uniquesubject.

In the mean time, StarTeam 5.1 users can use the MPXPoll utility to correctthis situation as described below.

The MPXPoll Utility is a console application that accepts a single parameteras shown below:

MPXPoll -s

where

is a Message Broker connection string such as"Host1" or "tcp:123.45.67.89:5101". The utility must be runfrom a console window on a machine on which the StarbaseMPX Event Transmitter,the Starbase Message Broker, or the StarTeam Win32 client has been installed.This is because MPXPoll uses the same run-time DLLs installed for thesecomponents.

When run, MPXPoll first connects to the Message Broker with the givenaddress. If successful, it then publishes a "general poll" message toall StarbaseMPX Event Transmitters within the MPX cloud. Normally, each EventTransmitter responds to this poll with general information about itsenvironment, which the MPXPoll utility will display in the console window. Anexample output is shown below:

C:>mpxpoll -s 1js2
Connecting to project on RTserver.
Using tcp protocol.
Message from RTserver: Connection established.
Start subscribing to subject .
Polling for StarbaseMPX Event Transmitters.
Waiting for responses...
Transmitter for Server GUID: 54bfdc8a-1a83-11d6-b191-00c04f792e5f
Starbase server host: prodserver
Starbase server PID: 188
Starbase server userid: StarTeam
Message Broker connection: tcp:1js2:5101
Message Broker id: /_1js2_2568
Transmitter for Server GUID: be5ee3b0-c719-49c6-a1a1-f493764a03f5
Starbase server host: 1js2
Starbase server PID: 2580
Starbase server userid: JSmith
Message Broker connection: tcp:1js2:5101
Message Broker id: /_1js2_2568
2 StarbaseMPX Event Transmitters responded.

This output shows two Event Transmitters responding, one on host "prodserver"and one on host "1js2". The responses indicate that these EventTransmitters are working normally. If an Event Transmitter has been disconnectedfrom the MPX cloud, it will not be able to send a response. Furthermore, itsassociated Message Broker will detect that its connection has been broken andwill remove it from its tables. Note that the Message Broker may take a minuteor two before fully detecting and removing a disconnected Event Transmitter.Once the Event Transmitter has been removed, it will be able to reconnectwithout receiving the "not unique" error.

The MPXPoll utility can be downloaded here,or by contacting Starbase Support.

When to use: The MPXPoll application can be used at any time, even when noconnections are currently suspected. When the "not unique" error isobserved by viewing the Starbase server log file, the MPXPoll application can beused to correct this situation.

Note that MPXPoll is only applicable to StarTeam 5.1 environments withStarbaseMPX installed. The utility will no longer be needed with the StarTeam5.2 release.

Old KB# 28510
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