Registrations are now open. Join us today!
There is still a lot of work to do on the wiki yet! More information about editing can be found here.
Already have an account?

Microsoft KB Archive/174307

From BetaArchive Wiki

Article ID: 174307

Article Last Modified on 10/26/2007


  • Microsoft Message Queue Server 1.0
  • Microsoft Message Queuing 2.0
  • Microsoft Message Queuing 3.0
  • Microsoft Message Queuing 4.0

This article was previously published under Q174307


This article describes the files in the Msmq\Storage and Msmq\Storage\Lqs directories.

This information is useful, for example, if you want to manually inspect the properties of a private queue or determine the disk space being used for the storage of messages.


Files in the Msmq\Storage directory

File names with an .mq extension represent memory-mapped files in which messages are stored.

The .mq file name extension will be prefixed with a letter representing the type of messages it is tracking:

r - Express messages (Note that express messages are normally held in RAM, not disk. This file is used when there is no more available RAM.)

p - Persistent (recoverable) messages

j - Journal messages

l - Indexing bitmap for interpreting the journal or recoverable files.

Note An .mq file does not identify or map to a unique queue. Messages from multiple queues may be held in one .mq file, or messages from a single queue may span multiple .mq files. A single message cannot span multiple files (hence the 4 MB limit in size).

The QMLog file is a history of transactional message processing. When the log is full, the oldest log data is overwritten as new entries are made.

To allow this continuous, cyclic writing to the QMLog, the state of receiving ordered messages and the state of all active transactions is periodically saved to the following files (respectively):


The .lg1 and .lg2 files are written to in an alternating pattern, to ensure that one of the pair will persist if the other is damaged during a write.

Files in the Msmq\Storage\Lqs directory

Files in this directory are text files that describe properties of the local queues. They are accessed as an .ini file.

File names formatted nnnnnnnn.hhhhhhhh represent private queues. The nnnnnnnn portion is the queue number (included in the direct format name for the queue). The hhhhhhhh extension is a hash of the path name used for quick lookup.

File names formatted aaaaaaaabbbbccccddddeeeeeeeeeeee.hhhhhhhh represent local public queues. The 32 character portion of the file name to the left of the period is the GUID of the queue. The hhhhhhhh extension is again a hash of the path name.

Additional query words: filename filenames pathname

Keywords: kbproductlink kbenv kbinfo KB174307