pub/sub, synchronous or async

I thought I knew how pub/sub worked, but apparently not.

Given a service pub1 that publishes two instances of Doc1. A trigger subscribes to Doc1, with a target service on sub1. Assume that sub1 takes 5 seconds to run.

I would expect the two activations of sub1 to take about 5+ seconds of elapsed time. Instead, the actual time is 10+ seconds.

This tells me that the two instances of Doc1 are run serially, not in parallel. Is that correct?

That is the default behavior of a trigger, but you can change it to process concurrently using n threads. Of course, if preserving the publication order is important then it is usually necessary to set the trigger to process serially.


Thanks Mark. Per your advice I changed the properties of the trigger and got the desired results.

Thanks for your prompt reply.

Details of configuring triggers can be found in the Publish-Subscribe Developer’s Guide Version 6.5 located in the webm_home\Developer\doc\guides folder.

The section on “Selecting Document Processing” contains the following information about the behavior of the “Concurent” processing mode: