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Otherwise, you may need to duplicate the existing user directory date (tables with prefix of dir_ in the database) to the new server.

Migration of Running Process Instances

Before We Begin

Before attempting anything, always perform a backup in any (app or database) servers that you will be working on. This is so that there's always something to fallback on, just in case!

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1. Make a list of process instances that are still running.
2. Copy these data over to the target server.
   1. Form Data from the database
   2. File Upload from wflow/app_formuploads
3. Now that form data and its uploaded files are available in the target server, we can migrate process instances over to the target server.

To verify the data that you have copied them over, make use of CRUD Menu or List Menu in the app to browse through the data imported in.

Migrate Process Instances

Then, perform the following steps, starting with just 1 process instance. The steps below can be performed using the utility app available for download in this article.

1. Based on the list compiled in step 1, start new process instance in the new server using the same user with reference to the form record ID. Here's a sample of a process instance that is still running.
   
   Figure 4: Process Instance View
   
   In Figure 4 above, there are 3 vital information we need, and use them to call JSON API in the target server by using JSON API#web/json/workflow/process/start/(*:processDefId). We will also need to copy any workflow variable data over to the new instance too. We can pass on var_* parameters to set the workflow variables' values accordingly.
   
   At this point of time, the new process instance would be waiting at its very first activity.
   
   IMPORTANT NOTE: If you have tools that run right at the start of the process flow, this may cause manipulation of form data state. Take note of potential changes that may occur and devise a way to preserve original data/state.
2. Once a new process instance is started, note down the process instance ID generated, and we will then need to make use of JSON API#web/json/monitoring/activity/start/(*:processId)/(*:activityDefId) to resume the activity where it supposed to be, in the original server.
   
   
   Figure 5: Process Instance View Highligting Open Activity Instances
   
   NOTE: Depending on how many pending activities that we may have in the specific process instance, we may need to make multiple calls to this JSON API. Take note that in the first of such call, we will need to set the "abortCurrent" parameter value to "true" so that it aborts the first default pending activity instance. Subsequently, set "abortCurrent" parameter to "false".
   
   IMPORTANT NOTE: The assignee of the resumed activity instance may not be correct if its participant mapping relies on performer of past activities. This is because past activities' data is NOT available in the target server.
3. In the target server, attempt to continue with the process assignment, as usual, through Datalist Inbox Menu or Inbox Menu in your app, ideally, to the very end, to validate that it is working as expected.

Once we have validated and refined the steps to migrate a process instance, we can then move on to migrate more process instances over.

Utility App for Migration of Running Process Instances

We have created an utility app to perform the 3 steps listed above. Please refer to the diagram below to understand on how to use it.

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