The full text of the message is "Running the Merge Agent process at this time would exceed the maximum number of processes allowed by this publication. The process will run when resources become available." It couldn't be put on the title.
We have a merge publication on a database. While a subscriber is synchronising, the above message often appears and synchronisation stalls for several minutes and might even time out.
The publication's "maximum concurrent processes" setting is 20, and using SSMS's activity monitor I see only 4 processes that seem to be related to this publication. In any case, there is only one subscriber for the publication and so it seems unlikely it could be using 20 processes.
Am I correct in my assumption above (that one subscriber shouldn't use 20 processes) and, if I am, what could be causing this problem?
Searching Google for the message's text brings only two results.
This is a merge publication where both publisher and subscriber use SQL Server 2008 R2.