Chapter 4 . Managing MessageQ

This chapter contains topics that describe how to manage MessageQ software on your system from the command line or from the MessageQ Monitor utility.

The topics include:

Using the Monitor Utility

The Monitor utility is a MessageQ application that allows you to monitor and control the performance of your MessageQ for UNIX system.

This chapter describes how the Monitor utility lets you manage MessageQ functions such as:

Using the Monitor utility requires that you be connected to a bus and group. If you set the DMQ_BUS_ID and DMQ_GROUP_ID environment variables prior to invoking the Monitor utility, you will connect to that bus and a group when you invoke the Monitor utility. If you do not set the environment variables before invoking the Monitor utility, you must connect to the bus and group using the Monitor utility. The Monitor utility provides a character-cell and Motif user interface.

Invoking the Character-Cell Interface

If your monitor does not have graphics capabilities, you can invoke the character-cell user interface. To invoke the character-cell user interface without attaching to a bus or group, enter the following command: 

# dmqmonc

To invoke the character-cell user interface and specify the bus and group, use the following command format: 

# dmqmonc -b bus_id -g group_id

Where:

-b bus_id

bus number

-g group_id

group number

The bus and group you specified appear at the bottom of the main window. If you did not specify a bus and group, the bus and group listed will be specified by the environment variables DMQ_BUS_ID and DMQ_GROUP_ID.

To monitor or control your MessageQ groups or buses, enter the letter or number associated with the activity you want to perform. In most cases, a secondary screen appears allowing you to monitor or control the performance of your messaging system. To return to the main menu from any secondary screen, press Return.

Invoking the Motif User Interface

To use the Motif user interface, you must have a graphics monitor or workstation, and you must set the UIDPATH environment variable. Enter the following command to set this variable: 

# setenv UIDPATH /usr/lib/X11/uid/%U:/usr/kits/DMx400/bin/%U

The DMx can be either of the following:

DMA

Digital UNIX systems

DMQ

Other UNIX systems

You must also set the NLSPATH environment variable, which allows MessageQ to properly translate error codes into text strings. To set the NLSPATH variable, enter the following command: 

% setenv NLSPATH /usr/lib/nls/msg/%N:/usr/kits/DMx400/lib/nls/msg/%N

To invoke the Motif user interface, enter the following command: 

# dmqmonm

Use the File menu item to subsequently attach to a bus and group.

You can also invoke the Monitor utility and specify the bus and group on the command line, as shown in the following format: 

# dmqmonm -b bus_id -g group_id

Where:

-b bus_id

bus number

-g group_id

group number

You can run the Motif user interface from a character-cell monitor by setting the display. For example, if you are running the Monitor utility on node abc, you can display the Motif user interface on node xyz by using the following commands:
csh Syntax sh Syntax

# setenv DISPLAY xyz:0.0

# DISPLAY=xyz0.0
# export DISPLAY

# dmqmonm -b bus_id -g group_id

dmqmonm -b bus_id -g group_id

Connecting to the MessageQ Environment

Before running a program that uses MessageQ, you must set the environment to identify the message queuing bus and the message queuing group with which the program will be associated. A MessageQ program associates itself with a specified bus ID and group ID at runtime by obtaining the values of the DMQ_BUS_ID and DMQ_GROUP_ID environment variables.

To set environment variables that designate a bus and group ID using csh syntax, enter the following commands: 

# setenv DMQ_BUS_ID bus_id
# setenv DMQ_GROUP_ID group_id

To set environment variables that designate a bus and group ID using sh syntax, enter the following commands: 

# DMQ_BUS_ID = bus_id
# export DMQ_BUS_ID
# DMQ_GROUP_ID = group_id
# export DMQ_GROUP_ID

You must set these environment variables each time you install a new version of MessageQ for UNIX software.

Connecting to a Group From the Monitor Utility

You can connect to a group from the MessageQ Monitor utility. The following procedures describe how to connect to a group using the character cell or Motif interface.

Connecting to a Group From the Character-Cell Interface

Use the following procedure to connect to a group:

  1. Select Connect to Group from the Main menu.

  2. Enter the Group number you want to connect to.

Connecting to a Group From the Motif Interface

Use the following procedure to connect to a group:

  1. Select the File pull-down menu.

  2. Select Connect.

  3. Enter the Bus ID.

  4. Enter the Group ID.

  5. Select OK.

Starting a Message Queuing Group

To start MessageQ for UNIX systems, you must invoke the MessageQ startup procedure (dmqstartup) to start each referenced group in the group initialization file.

The MessageQ startup procedure executable image is dmqstartup, and is run interactively by entering the following command: 

# dmqstartup -b bus_id -g group_id -f filespec -n group_name [-l logfile_name]

Where:

-b bus_id

Numeric bus ID; maximum of four digits.

-g group_id

Numeric group ID; maximum of five digits.

-f filespec

The pathname and file specification of the group initialization file.

-n group_name

Descriptive alphanumeric name for this group. No spaces or special characters are allowed.

-l logfile_name

Optional log file name. You must specify a pathname and file specification. Note that if you do not use a log file, the output displays to the screen in an "unformatted" manner.

MessageQ uses the bus ID and the group ID to locate configuration information for a given application. See the topic in the previous section for more information.

You must set the NLSPATH environment variable, which allows MessageQ to properly translate error codes into text strings. MessageQ error or informational messages are displayed on your monitor screen. To set the NLSPATH variable, enter the following command: 

% setenv NLSPATH /usr/lib/nls/msg/%N:/usr/kits/DMx400/lib/nls/msg/%N

Starting a Group From the Monitor Utility

You can start a group from the MessageQ Monitor utility. The following procedures describe how to start a group using the character cell and Motif interfaces.

Starting a Group From the Character-Cell Interface

Use the following procedure to start a group:

  1. Select Start Group from the Main menu.

  2. Enter the bus number.

  3. Enter the group number.

  4. Enter the group name.

  5. Enter the full path to the Group Initialization File.

    For example: /user3/users/jones/bigfile.init

  6. Enter the full path for the log file name (optional).

    For example: /user3/users/jones/group10.log

    Note: If you do not use a log file, the output displays to the screen in an "unformatted" manner, making it difficult to read.

    MessageQ displays the message: Group# (#) is started.

Starting a Group From the Motif Interface

Use the following procedure to start a group:

Select the Manage pull-down menu.

Select Start.

  1. Enter the bus number.

  2. Enter the group number.

  3. Enter the group name.

  4. Enter the full path to the Group Initialization File.

    For example: /user3/users/jones/bigfile.init

  5. Enter the full path for the log file name (optional).

    For example: /user3/users/jones/group10.log

    Note: If you do not use a log file, the output displays to the screen in an "unformatted" manner, making it difficult to read.

  6. Select OK.

Shutting Down a Running Group

MessageQ offers a shutdown procedure to shut down a running group immediately. The MessageQ shutdown procedure executable image is dmqshutdown, and is run interactively by entering the following command: 

# dmqshutdown -b bus_id -g group_id

Where:

-b bus_id

Numeric bus ID; maximum of four digits.

-g group_id

Numeric group ID; maximum of five digits.

The group shutdown procedure stops all queues immediately without draining the messages in the queues. Further, it stops all links immediately and provides an orderly shutdown of all MessageQ processes.

Shutting Down a Group Using the Monitor Utility

You can shutdown a group from the MessageQ Monitor utility. The following procedures describe how to shutdown a group using the character cell or Motif interface.

Shutting Down a Group From the Character-Cell Interface

Use the following procedure to shutdown a group:

  1. Select Shutdown group from the Main menu.

    MessageQ displays the question: Stop gracefully, y or n?

  2. Enter y or n.

    If you enter y, MessageQ stops all queues in the group, allowing them to be emptied. Applications can continue to read messages from the queues until all are empty. However, applications cannot place messages in the queues. After all the queues are empty, the MessageQ processes in the group will terminate.

    If you enter n, MessageQ terminates all MessageQ processes in the group immediately. When the group is stopped, messages can no longer be delivered to the queues and all pending messages in the queues are lost. You can use this option to stop a group immediately even after selecting that the group stops gracefully.

  3. MessageQ displays the question: 

    Do you really want to shutdown group #?

  4. Enter y or n.

Shutting Down a Group From the Motif Interface

Use the following procedure to shutdown a group:

  1. Select the Manage pull-down menu.

  2. Select Group.

  3. Select Fast Shutdown or Soft Shutdown.

    If you select Soft Shutdown, MessageQ stops all queues in the group, allowing them to be emptied. Applications can continue to read messages from the queues until all are empty. However, applications cannot place messages in the queues. After all the queues are empty, the MessageQ processes in the group will terminate.

    If you select Fast Shutdown, MessageQ terminates all MessageQ processes in the group immediately. When the group is stopped, messages can no longer be delivered to the queues and all pending messages in the queues are lost.

  4. MessageQ displays a warning: 

    Are you sure you really want to shutdown group #?

  5. Select OK.

Starting a Cross-Group Connection

You can start a cross-group connection, also called a Link, using the MessageQ Monitor utility. The following procedures describe how to start a Cross-Group connection using the character cell or Motif interface.

Starting a Cross-Group Connection From the Character-Cell Interface

Use the following procedure to start a cross-group connection:

  1. Select Start Xgroup link from the Main menu.

    MessageQ prompts you to enter the number of the group to which you want to form a cross-group connection.

  2. Enter the cross-group number.

    A successful return code is indicated with the message: 

    Link to Group # is started.

Starting a Cross-Group Connection From the Motif Interface

Use the following procedure to start a cross-group connection:

  1. Select the Manage pull-down menu.

  2. Select Link.

  3. Select Start.

  4. Select a link number from the list.

  5. Select OK.

Stopping a Cross-Group Connection

You can stop a cross-group connection using the MessageQ Monitor utility. The following procedures describe how to stop a cross-group connection using the character cell or Motif interface.

Stopping a Cross Group Connection From the Character-Cell Interface

Use the following procedure to stop a cross-group connection:

  1. Select Stop Xgroup link from the Main menu.

    MessageQ prompts you to enter the number of the group for which you want the cross-group connection stopped.

  2. Enter the cross-group number of the link you want to stop.

    MessageQ immediately disables the link, which causes all cross-group communication with the selected group to cease. A successful return code is indicated with the message: 

    Link to Group # is stopped.

    Note: To restart the link, you must issue the start command from the node that stopped the link. The link cannot be restarted from the remote node with which it was communicating.

Stopping a Cross Group Connection From the Motif Interface

Use the following procedure to stop a cross-group connection:

  1. Select the Manage pull-down menu.

  2. Select Link.

  3. Select Fast Shutdown.

  4. Select a link number from the list.

  5. Select OK.

Starting a Queue

You can start a queue using the MessageQ Monitor utility. The following procedures describe how to start a queue using the character-cell or Motif interface.

Starting a Queue From the Character-Cell Interface

Use the following procedure to start a queue:

  1. Select Group Information from the Main menu.

  2. Select Queue Start from the Group Information menu.

  3. Enter the queue number you want started.

Starting a Queue From the Motif Interface

Use the following procedure to start a queue:

  1. Select the Manage pull-down menu.

  2. Select Queue.

  3. Select Start.

  4. Select a queue number from the list.

  5. Select OK.

Stopping a Queue

You can stop a queue using the MessageQ Monitor utility. The following procedures describe how to stop a queue using the character-cell or Motif interface.

Stopping a Queue From the Character-Cell Interface

Use the following procedure to stop a queue:

  1. Select Group Information from the Main menu.

  2. Select Queue Stop from the Group Information menu.

  3. Enter the queue number you want stopped.

    MessageQ displays the question: 

    Stop gracefully, y or n?

  4. Enter y or n.

    If you enter y, MessageQ stops the specified queue in an orderly manner. When stopped gracefully, a queue will no longer accept new messages; however, it does allow messages to be read until the queue is empty. When the queue is empty, the queue will be placed in a stopped state.

    If you enter n, MessageQ stops the specified queue immediately. A stopped queue will not accept any new messages and will not allow messages to be read from the queue. You can use this option to stop a queue immediately even after selecting that the queue stops gracefully.

Stopping a Queue From the Motif Interface

Use the following procedure to stop a queue:

  1. Select the Manage pull-down menu.

  2. Select Queue.

  3. Select Fast Shutdown or Soft Shutdown.

  4. Select a queue number from the list.

  5. Select OK.

Starting and Stopping the CLS

You can start and stop the CLS from the MessageQ Monitor utility. The following procedures describe how to start and stop the CLS using the character-cell or Motif interface

Starting the CLS From the Character-Cell Interface

Use the following procedure to start the CLS:

  1. Select Group Information from the Main menu.

  2. Select CLS Start from the Group Information menu.

  3. Enter the endpoint number.

  4. Enter 1 for TCP/IP or 2 for DECnet.

Starting CLS From the Motif Interface

Use the following procedure to start the CLS:

  1. Select the Manage pull-down menu.

  2. Select CLS.

  3. Select Start.

  4. Enter the endpoint number.

  5. Enter 1 for TCP/IP or 2 for DECnet.

Stopping CLS From the Character-Cell Interface

Use the following procedure to stop the CLS:

  1. Select Group Information from the Main menu.

  2. Select CLS Stop from the Group Information menu.

  3. Enter the endpoint number.

  4. Enter 1 for TCP/IP or 2 for DECnet.

Stopping CLS From the Motif Interface

Use the following procedure to stop the CLS:

  1. Select the Manage pull-down menu.

  2. Select CLS.

  3. Select Fast Shutdown.

  4. Enter the endpoint number.

  5. Enter 1 for TCP/IP or 2 for DECnet.

Restricting Remote Access to CLS

The CLS security file is a text file containing a table of client entries. Each client entry contains a list of endpoints and queues which the client may use. CLS uses the security file to restrict access by remote clients to those endpoints and queues. MessageQ groups can have their own separate security files, or can share one file jointly.

You can create a security file in one of two ways:

Edit the template file that is distributed in the /templates directory of the media kit.

On Windows systems, you can use the Security Utility to edit the security file.

For LIBRARY client servers on UNIX systems, a template security file is available at the following location: 

/usr/kits/DMx400/templates/dmqclsec.txt

Begin by making a copy of the template security file. Then, edit the copy to remove the sample entries and add entries for the client systems in your environment. Copy the file to its target location and then associate the security file with the message queuing group. Refer to Table 3-5 for a description of how to associate a security file with a message queuing group.

When a CLS is started, it loads the security file specified in the %CLS section of the group initialization file. If no security file is specified, CLS will not restrict access by remote clients. Each CLS can have a separate security file, or a security file can be shared by multiple CLS processes.

For information about the CLS Security Utility, refer to the MessageQ Client for Windows User's Guide.

Managing Message Recovery Services

MessageQ Message Recovery Services (MRS) provide a mechanism for guaranteed message delivery by storing messages on disk and automatically attempting redelivery until the message is received by the target system.

If you enabled MRS as part of your group configuration, you can replay the contents of postconfirmation or dead letter journals using the Journal Replay utility. You may also print the contents of postconfirmation, dead letter, destination queue, or store-and-forward journals using the Journal Dump utility.

All journal file names are 16 characters long. Each journal file name contains a 12-digit filename, a dot, and a 3-character extension that identifies the journal type. Note that journal file names are unique within a group, but not between groups. Therefore, message queuing environments running more than one message queuing bus must ensure that journal files are not accidentally shared by groups running on different message queuing buses.

Valid journal filenames are of the format:
Format Journal Type

ggggqqqqssss.DQF

Destination Queue File

ggggrrrrssss.SAF

Store and Forward

ggggssssssss.PCJ

Postconfirmation Journal

ggggssssssss.DLJ

Dead Letter Journal

Where:

g

Four-digit local group number in hexadecimal.

q

Four-digit queue number in hexadecimal.

r

Four-digit remote group number in hexadecimal.

s

File sequence number in hexadecimal within a set of files.

Replaying Journal Messages

The Journal Replay utility lets you resend the contents of postconfirmation or dead letter journals. The Journal Replay utility can use live recovery journals; however, if the journal file is currently in use, you must make a copy of the file before you can replay it. The Journal Replay utility can resend the entire journal file.

Messages sent from the postconfirmation or dead letter journal will be sent using the same source address, target address, delivery mode, and user notification. If the original message requested notification, the notification message is directed to the journal replay process instead of the original sender program.

To invoke the Journal Replay utility, enter the following command syntax. Switches enclosed in parentheses indicate optional command qualifiers. 

dmqjplay -b bus -g group -m mode -t journal_type -j journal_path [-l log_path]

Table 4-1 describes the command options for dmqjplay.
Table 4-1 Journal Replay Utility Command Options
Switch Argument Description

-b

bus

Numeric Bus ID; maximum of 4 digits.

-g

group

Numeric Group ID; maximum of 5 digits.

-m

mode

A constant identifying the selected processing mode, as follows:

r=replay: Retransmit the contents of the journal file and delete each message when it reaches the delivery interest point.

t=transfer: Retransmit the contents of the journal file and delete each message when it reaches the delivery interest point.

d=delete: Delete the contents of the selected journal.

-t

journal_type

A constant that designates the file to be replayed, as follows:

d Dead letter

p Postconfirmation

-j

journal_path

The pathname of the dead letter journal or postconfirmation journal that is to be replayed.

-l

log_path

Optional log file. You must specify a pathname and file specification.

Printing Journal Files

The Journal Dump utility lets you produce a formatted report of the contents of a dead letter journal, postconfirmation journal, destination queue file, or a store and forward file. The Journal Dump utility can be used to print a live journal file if it is not in use. If the journal file is in use, you must halt the message recovery system for the group, and then use the Journal Dump utility to print the contents of the journal file.

To run the Journal Dump utility, enter the following command syntax (switches enclosed in parentheses indicate optional command qualifiers): 

dmqjdump -b bus -g group -q queue -t journal_type -h header_type
-m message_format -j journal_path [-d] [-l log_path] [-o output_file] [-n number]

Table 4-2 describes the command options for dmqjdump.
Table 4-2 Journal Dump Utility Command Options
Switch Argument Description

-b

bus

Numeric Bus ID; maximum of 4 digits

-g

group

Numeric Group ID; maximum of 5 digits

-q

queue

Queue number

-t

journal_type

A constant that designates the type of journal to be replayed, as follows:

dlj ­ Dead letter journal

dqf ­ Destination queue file

pcj ­ Postconfirmation journal

saf ­ Store and forward file

-h

header_type

A constant that designates the header type, as follows:

summary ­ Displays the source target, type and class of each message that is dumped.

detail ­ Displays internal header fields of each message that is dumped.

-m

message_format

Specifies a valid message format, as follows:

hex ­ Displays output in hexadecimal bytes with ASCII translation

script ­ Displays output in MessageQ script format

-j

journal_path

The pathname of the dead letter journal, postconfirmation journal, destination queue, or store and forward file that is to be dumped

-d

Deletes messages from the journal as they are dumped

Note: This option should be used with caution.

-l

log_path

Optional log file. You must specify a pathname and file specification.

-o

output_file

A pathname and file specification to receive the dump output

-n

number

The number of messages in the file you want to print, starting with the first message

Changing Group Characteristics at Runtime

You can use the Loader utility to dynamically reload the group initialization file without having to shutdown and restart MessageQ. The Loader utility lets you enter modified settings or parameter values into a running group initialization file.

To run the Loader utility, enter the following command format: 

dmqloader -b n -g n -f init_file_path [-l logfile]

Where:

-b

Numeric Bus ID; maximum of 4 digits

-g

Numeric Group ID; maximum of 5 digits

-f

The pathname and file specification of the group initialization file

-l

Optional log file. You must specify a pathname and file specification

Table 4-3 describes the parameters in the group initialization file that can be modified at runtime.
Table 4-3 Modifiable Parameters in the Group Initialization File
Section in Initialization File Parameter Runtime Restriction?

%PROFILE

ACCEPT_KILL_COMMAND

ATTACH_TMO

DEFAULT_NAMESPACE_PATH

NO

NO

NO

%CLS

MAX_CLIENTS



SECURITY_FILE

YES. CLS must be stopped. This parameter applies to OpenVMS systems only.

YES. CLS must be stopped.

%XGROUP

RECONNECT

RECONN_TIMER

WINDOW_DELAY

WINDOW_SIZE

YES. The link must be disabled.

YES. The link must be disabled.

YES. The link must be disabled.

NO

%QCT

BYTE_QUOTA

MESSAGE_QUOTA

MESSAGE_QUOTA_ENABLE

BYTE_QUOTA_ENABLED

TYPE

OWNER

MRS_CONFIRM_STYLE

PERM_ACTIVE

SECURITY_ENABLED

NO

NO

NO

NO

YES. The queue must be empty and have no processes attached. When changing a primary queue to a secondary queue, the primary queue cannot have any secondary queues defined.

YES. The queue must be empty and have no processes attached. To set this parameter to a value other than zero, the queue must be defined as a secondary queue, and the owning queue must be defined and be a primary queue.

NO

YES. The queue must be empty and have no processes attached.

NO

Enabling Quotas

The MessageQ Monitor utility lets you enable or disable quotas on permanent queues that you previously defined in the %QCT section of the group initialization file. You can enforce quotas on the maximum number of collected messages and bytes that can reside in a given queue. For more information on setting these quotas in the %QCT section, see Defining Queues in the Queue Configuration Section in Chapter 3.

If you are not concerned whether your application exceeds quotas, you should disable quotas to increase performance and reduce screen clutter.

Enabling or Disabling Quotas From the Character-Cell Interface

Enable or disable quotas using the following procedure:

  1. Select Enable Quotas or Disable Quotas from the Main menu.

    MessageQ displays the message: Quotas enabled or Quotas disabled.

Enabling or Disabling Quotas From the Motif Interface

Use the following procedure to enable or disable quotas:

  1. Select the Manage pull-down menu.

  2. Select Quotas.

  3. Select Enable or Disable.

Setting Security for Queues

MessageQ lets you protect a queue from unauthorized reading by implementing an Access Control List (ACL) queue security. When set, the queue security prevents a process from attaching to a queue if the process does not have privilege to open a protected file on disk. MessageQ implements this security feature by creating a directory tree structure in the /var/tmp/dmq directory. The pathname to the security file for a selected queue is a combination of the bus, group, and queue number as follows: 

/var/tmp/dmq/b_xxxx/g_yyyy/acl/q_zzz

Where:

xxxx

The number of the bus in decimal with leading zeros.

yyyy

The number of the group in decimal with leading zeros.

zzz

The number of queues in decimal with leading zeros.

For example, the security file for queue 50 in group 2 of bus 777 is: 

/var/tmp/dmq/b_0777/g_00002/acl/q_050

To configure a queue to use queue security, place the letter "y" in the last column of a queue entry in the %QCT section of the group initialization file, as follows: 

QUEUE1  1  64000  100   None  .  P   0  .  N    Y

(See the Defining Queues in the Queue Configuration Section topic in Chapter 3 for more information on how to configure a queue.)

If you specify queue security and the security file does not exist, you will not be able to attach the queue and you will receive the error status PAMS__NOACL. If the security queue file exists, you must have read/write access to the security file to attach the queue. If you cannot open the file for read/write access, the attach operation will fail and return the error status PAMS__NOPRIV.

The commands used to set file protections can vary depending on the file system. For most UNIX systems, the commands chmod, chown, and chgrp are used to set file protection. For more information about setting file protection, refer to the user documentation for the file system you are using.

Setting Quotas for Dynamic Queues

Queue numbers with a number greater than Temporary Queue (FIRST_TEMP_QUEUE) are dynamically assigned. The BYTE_QUOTA and MSG_QUOTA values for dynamically assigned queues are set from the TEMPLATE entry in the %QCT section. Do not change any other value in the TEMPLATE queue entry.

Enabling Queue Quotas for Selective Queues

Previous versions of MessageQ required you to enable or disable queue quotas for an entire message queuing group. However, you can now enable queue quotas on a per queue basis on UNIX systems. You can enable or disable message and byte quotas for a selected queue at startup by setting the Quota Enable field for each entry in the %QCT section of the group initialization file. contains the values that you can specify for the QUOTA_ENABLED attribute.

You can use the Monitor utility to enable or disable message and byte quotas for a selected queue at runtime. (See the Enabling Quotas topic for more information.)

Defining Timeout Intervals for Link Drivers

The MessageQ link drivers provide parameters that let you define timeout intervals for testing the state of a cross-group connection or aborting a connection with a cross-group link. These parameters are implemented as the following environment variables:

DMQLD_PING_INTERVAL

Specifies the amount of time a Link Sender process should wait before issuing another ping message to test the state of a connection. The ping interval is the number of seconds between tests. The default value is 30 seconds.

DMQLD_PING_TIMEOUT

Specifies the amount of time a Link Sender should wait for a response to a ping message before aborting. The default value is 60 seconds.

If you must use a value other than the default, set both environment variables before starting your group.