EM 12.1.0.4: Agents Failed to Upload with EMD upload error:full upload has failed: Upload Recent Sending Statistics

Problem

After upgrading the OEM to 12.1.0.4, some of the agents failed to upload the files.

$ emctl upload agent
Oracle Enterprise Manager Cloud Control 12c Release 4
Copyright (c) 1996, 2014 Oracle Corporation.  All rights reserved.
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EMD upload error:full upload has failed: Upload Recent Sending Statistics
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Avg send time=0.0 milliseconds
Backoff Event List
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Backoff event : channel=Metadata expiration at 2014-09-02 12:16:19 CDT
Backoff event : channel=Metadata expiration at 2014-09-02 12:16:21 CDT
Backoff event : channel=Metadata expiration at 2014-09-02 12:16:15 CDT
Backoff event : channel=Metadata expiration at 2014-09-02 12:16:17 CDT
Backoff event : channel=Metadata expiration at 2014-09-02 12:16:42 CDT
Backoff event : channel=Metadata expiration at 2014-09-02 12:17:17 CDT
Upload Failure List
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Connection Event List
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Upload timed out before completion.
Number of files to upload before the uploadNow call: 53, total size (MB): 0.061219215
Remaining number of files to upload: 61, total size (MB): 0.06959915 (TIMEOUT)

Cause

Issue is due to a bug on the OMS side.

BUG 19458672 - High contention from metaver upgrade callback if default metric keys don't exis
Due to this bug, repository database is heavily loaded and wont accept files from the Agents.
 

Solution

Apply Patch 19458672 on OMS Home as per the readme instructions.
 

References

Metalink Doc : Doc ID 1932205.1