MQRC 2019: Object handle error

What it means

MQOPEN returns an object handle for the queue, topic or other object it opened. Later calls such as MQGET, MQPUT, MQINQ, MQSET and MQCLOSE pass that handle back. If the queue manager doesn't recognise the handle, the call fails with MQCC_FAILED and reason 2019.

Like 2018, this is a program error. The handle may never have been set because MQOPEN failed, it may have been closed already, or it may belong to a thread that doesn't own it. Another thread may also have closed a shared handle. The same code comes back when MQGET or MQPUT is given the handle of an object that isn't a queue, for example a handle opened on the queue manager object only to inquire on its attributes.

In Java and .NET the MQ classes manage handles for you, so 2019 there usually means the program used a queue object after closing it or after its connection ended.

Common causes

• MQOPEN failed and the program didn't check the reason code, then used the empty handle on MQGET or MQPUT.
• The program closed the queue and later used the same handle, for example a close in an error path followed by a retry that skips the reopen.
• A multithreaded program uses a handle on a thread other than the one that opened it, and the connection isn't shared.
• Another thread closed a shared handle while this thread still used it.
• The program passes the handle of a non-queue object, such as the queue manager or a namelist, to MQGET or MQPUT.
• The handle variable was overwritten by a buffer overrun or a parameter list that doesn't match the call.

How to find the problem

1. Find which call returned 2019 and trace the handle back to its MQOPEN. Check that MQOPEN returned MQCC_OK and that nothing changed the variable since.
2. Search the code for MQCLOSE calls on that handle, including in error handlers and cleanup routines that may run earlier than you expect.
3. On distributed MQ, an MQ trace (strmqtrc) or application activity trace records each call with its Hobj and shows where the handle was closed.
4. In a threaded program, log the thread ID with each open, use and close of the handle.
5. If the program reconnects after a broken connection (2009), check that it also reopens every queue. Handles from the old connection are no longer valid.

How to fix it

• Always check the result of MQOPEN before using the handle, and set the handle back to MQHO_UNUSABLE_HOBJ after MQCLOSE so a later use fails clearly.
• Reopen every object after a reconnect. Old handles don't carry over to a new connection.
• Keep handles on the thread that owns the connection, or use a shareable connection and coordinate closes.
• Open the queue itself for MQGET and MQPUT. Use the queue manager object handle only for MQINQ.
• Retrying with the same handle won't help. Fix the code path that loses or reuses it.

Technical reviewer: Albert Joseph, WND Software.

Last reviewed 2026-10-18 by the WND Software team. Written in our own words. For the full reference, check IBM’s MQ documentation for your version.