| Glossary | |
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A - B - C
- D - E - F - G - H - I -
J - K - L - M
N - O - P - Q - R - S
- T - U - V - W - X - Y - Z
| A | |
| Agent | amqzlaa0: The agent is responsible for maintaining all user connections to the queue manager. All user applications must first connect to a queue manager before they can use any of its services. There are usually multiple instances of an agent running at one time. Each agent is capable of managing multiple connections. |
| The sending program does not wait for confirmation that a message has been received before sending the next message to queue. The sending program proceeds with its own processing without waiting for a reply to its message. | |
| Automatic Channels | Automatic cluster channels are created during runtime by the queue manager to communicate with other cluster queue managers. Automatic channels are not defined, and they do not show as explicitly defined channels on the queue manager. |
| Automatic Listener | amqcrsta: The automatic listener starts the receiving end of a communication channel. It is configured to automatically run as a TCP/IP service provided by the host operating system and creates a separate process for each connection to the queue manager. |
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| B | |
| The backout count is a number indicating how many times a message has been processed under a transaction that has been rolled back. The queuing-aware framework uses this backout count to ensure that a message is only processed once by a server before being excepted. | |
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| C | |
| A channel is defined as a basic communication conduit by which messages are passed between queue managers. The channel mostly operates over TCP/IP and sockets. WebSphere MQ uses a sender channel and a receiver channel to complete the communication path between two or more queue managers. | |
| Channel Initiator | runmqchi: The channel initiator works in concert with the channel listener to process work. The channel initiator application reads from the initiation queue, SYSTEM.CHANNEL.INIT.QUEUE, waiting for trigger messages to arrive. The channel initiator starts the caller MCA, which then starts the sending end of a communication channel. |
| Channel Listener | amqcrsta: The channel listener works in concert with the channel initiator to process work. The channel listener starts the responder MCA, which starts the receiving end of a communication channel. Listeners will sometimes show as runmqlsr if they are started manually. |
| Checkpoint Processor | amqzllp0: The checkpoint processor works closely with the logger to implement the unit of work, commit, rollback and recovery mechanisms of the queue manager. |
| Cluster Queue | A cluster queue is a local queue that has been marked as available to the entire cluster. The queue manager in which it is defined is called the hosting queue manager. Cluster queues appear as local queues to enqueuing applications. |
| Cluster Queue Manager | A cluster queue manager is a member of a specific MQ cluster. All queue managers in the same MQ cluster must have a unique queue manager name. |
| Command Queue | All changes to the cluster, such as a new cluster queue, are transmitted to full repositories through the command queue (SYSTEM.CLUSTER.COMMAND.QUEUE). This queue is normally empty unless changes are being made to the cluster. |
| Command Server | amqpcsea: The command server is used to process queue manager system maintenance commands enqueued by user written application programs. |
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| D | |
| To receive a message from a queue (or read a message from a queue). | |
| DNS | The Domain Name System is used for storage and retrieval of certain network-related configuration settings. Queue manager connectivity information can be defined in DNS using SRV records. The naming convention “_cerner_<domain>_mqclient._tcp” is used for these SRV records. |
| Domain | A domain is a set of application servers and a physical database for a defined set of users, the clinicians’ working environment. An application domain can span multiple nodes. |
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| E | |
| To send a message to a queue (or write a message to a queue). | |
| Enterprise Java Servers | The Enterprise Java Server (EJS) framework uses MQ for synchronous queuing of non-persistent messages. |
| Exception Queue | Queue where messages that could not be processed are placed for requeuing. A message is placed in the exception queue when the server crashes while processing the message or the server is unable to process the message for some reason. The exception queue is only used for persistent messages (those delivered to RDM services). |
| Execution Controller | amqzxma0: The execution controller is the heart of a queue manager. It is the first application started when the queue manager starts. It starts all other processes, and therefore, is the parent process. It maintains a health watch over all processes it spawns. |
| Explicit Channels | Explicit cluster channels are channels that are defined using the RUNMQSC command “define channel”. All cluster queue managers must explicitly define one sender channel and one receiver channel, and they must point to a full repository. |
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| F | |
| Fastpath Channels | When fastpath channels are enabled, MQ client connections bypass the MQ agent processes and communicate directly with the queue manager. |
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| I | |
| When a message is enqueued to the cluster transmission queue, a trigger message is placed on the cluster initiation queue, SYSTEM.CLUSTER.INIT.QUEUE. This then triggers the channel initiator to start the caller MCA. | |
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| L | |
| Log files are used by WebSphere MQ to provide a file-backed store that is used to keep messages marked as persistent (available) across a queue manager and system reboots. It also plays a role in the transactional processing of a message by tracking a unit of work from its inception to completion. | |
| Logger | amqhasmx: The logger is responsible for all read/write activities to log files. The log files are used to maintain persistent messages and form the basis for transactional processing. |
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| M | |
| Manual Listener | runmqlsr: The manual listener starts the receiving end of a communication channel. It delegates new connections to multithreaded remote pool (amqrmppa) processes. |
| A message is a collection of data created by one application with the intention of sending that data to another application. Some messages are request messages, and some are reply messages. The sending and receiving applications must understand the format of the message. Messages can be either persistent or non-persistent. | |
| Message Compression | Message compression reduces the bandwidth required for transmission of messages across a network channel. Messages are compressed prior to being sent, and decompressed after being received. |
| Message Channel Agent (MCA) | The message channel agent is a triggered process that executes on both ends of a channel. A caller MCA is the initiator of activity on a channel, and a responder MCA starts as a result of this action. MCAs are triggered either by a channel initiator message or by the channel listener. |
| Message queuing is the act of writing (enqueuing, sending) and reading (dequeuing, receiving) a message from a queue. Reading and writing messages to a queue can be done at the same time. | |
| MQ Alert Server | mq_alert_server: MQ Alert Server monitors event queues. It logs WebSphere MQ events to the mqalert.mlg file. It is server number 29. |
| MQ Based Shared Server | MQ-based shared services (MQSS) functionality enables traditional shared services, such as CPM Script and Clinical Event, to use MQ for synchronous queuing of non-persistent messages. |
| MQ Client | MQ client connectivity allows applications to communicate with a queue manager over a network channel. |
| MQ (Client) Agent Server | mqa_server: MQ Agent Server is the remote client agent server. It is responsible for managing client asynchronous messaging. It is server number 28. |
| MQ Cluster | In Cerner Millennium, a MQ cluster is a networked group of queue managers associated with the same Cerner Millennium domain. |
| MQ_PROVIDER | Specifies the queue provider runtime library. |
| MQS.INI | MQS.INI is the system-wide initialization file for WebSphere MQ. It can be found in the QueueManager prefix directory. |
| MQ Shutdown Script | The MQ shutdown script stops all processes for a given queue manager, including the manual listener. On VMS, this script is named mq_<node>_<domain>_shutdown.com, and is located in sys$startup. On AIX and HP-UX, it is named mq_<node>_<domain>_shutdown.ksh and is located in $cer_mgr. |
| MQSS Audit | The MQSS_Audit utility can be used to audit whether the configuration settings for MQ Client and MQ-based Shared Services functionality match the recommended values. |
| MQ Startup Script | The MQ startup script starts all necessary processes for a given queue manager, including the manual listener. On VMS, this script is named mq_<node>_<domain>_startup.com and located in sys$startup. On AIX and HP-UX, it is named mq_<node>_<domain>_startup.ksh and located in $cer_mgr. |
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| N | |
| Non-Persistent Message | Non-persistent messages may be lost if an application or system failure occurs; this quality of service is acceptable due to the transient nature of these messages. Non-persistent messages are typically only stored in memory and not written to disk; providing much higher throughput levels than persistent messages. Synchronous services use only non-persistent messages. |
| A node is a physical back-end host system. | |
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| P | |
| Persistent Message | Persistent messages are guaranteed to survive any application or system failure, other than catastrophic loss of physical storage media. Asynchronous services use only persistent messages. |
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| Q | |
| QCPView | Queue Control Panel Viewer. Cerner-developed queue administrative tool for monitoring, maintaining, and troubleshooting the queuing system. |
| QM.INI | QM.INI is the queue manager-specific initialization file. Each queue manager has a qm.ini file located in the queue manager root path. |
| QUEMON | Queue Monitor. Cerner-developed system management tool used to monitor the queuing system in real time. |
| A queue is a persistent storage medium in which messages from one application can be stored and accumulated for processing by another application reading messages from that queue. | |
| Queue Control Panel | qcp_server: Queue Control Panel is the queuing administrative server. It provides the administrative services and management for QCPView and QUEMON. It is server number 27. |
| Queue Manager | A queue manager is a collection of collaborating applications that provide message queuing services to applications. |
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| R | |
| Reliable Delivery Message Server, or asynchronous server. | |
| Receiver Channel | clusrcvr: A queue manager receives cluster queue messages and repository updates from other queue managers via the cluster receiver channel. After a period of inactivity, the cluster receiver channel automatically shuts down. It starts up again for more incoming traffic. The naming convention for cluster receiver channels is “TO.<NODE>”. |
| Remote Pool Process | amqrmppa: Remote pool processes handle queue manager connections. Each remote pool process is multithreaded and can handle up to 64 connections; additional remote pool processes are automatically started as needed. |
| Repository | A repository contains information about the queue managers, queues, and channels that make up the MQ cluster. A full repository contains a complete set of information for all queue managers participating in a MQ cluster. A queue manager is marked as a full repository by placing the cluster name (cluster name correlates to the domain name) in the repos parameter of the queue manager definition. A partial repository contains a subset of the information contained in the full repository. It only stores the information required by the specific queue manager on the node. |
| Repository Manager | amqrrmfa: The repository manager is responsible for maintaining a directory of nodes, queues, channels, and queue managers that participate in a MQ cluster. |
| Repository Queue | The repository queue (SYSTEM.CLUSTER.REPOSITORY.QUEUE) is where the repository is stored as a series of messages. This queue is normally not empty. The repository manager process, amqrrfma, manages this queue. |
| RR Server | Request/Reply Server; handles synchronous messages. |
| RUNMQSC | IBM-developed administrative tool for managing WebSphere MQ objects. |
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| S | |
| Sender Channel | clussdr: The cluster sender channel (clussdr) defines one end of a communication channel. The cluster sender channel is used to send updates about the cluster to other repository queue managers within the cluster. It is also used to send messages destined for another queue manager within the cluster. After a period of inactivity, the cluster sender channel automatically shuts down. It starts up again when its services are needed. The naming convention for cluster sender channels is “TO.<NODE>”. |
| Server Connection Channel | svrconn: A queue manager uses server connection channels to accept incoming client connections. The naming convention for server connection channels is “FROM.<APPLICATION>” for channels with message compression enabled, and “FROM.NC.<APPLICATION>” for channels not using message compression. |
| Shared Service Queue Administrator | ssqa_server: The Shared Service Queue Administrator (SSQA) Server manages synchronous messaging queues. Its tasks include managing shared service request queue availability and purging expired messages. It is server number 36. |
| The sending program waits for a message to be dequeued before enqueuing the next message. The sending program does not proceed with its own processing until it receives a reply to its message. | |
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| T | |
| Transactional semantics are best described as the ability to ensure that a transaction is processed only once and never lost. It is implemented using the concept of units of work (UOW). A message processed under the control of a UOW can not be lost or processed more then once. This is guaranteed by WebSphere MQ. | |
| Transmission Queue | The cluster transmission queue, SYSTEM.CLUSTER.TRANSMIT.QUEUE, is the actual local queue used to store messages prior to transmission to other queue managers. The caller MCA reads messages off the transmission queue to send them across the channel. |
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| U | |
| A unit of work is a grouping of updates that are usually logically related and must all be successful for data integrity to be preserved. | |
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