Parallel Processing in Business Rule

I would be very careful before jumping into using Parallel.ForEach(), without considering the context/background.

For example, you might think of using Parallel.ForEach() over a list of Accounts or UD members : But you shouldn't be doing iterations over these sorts of members; should instead be using a DataBuffer. 

One might think about doing a Parallel.ForEach() across the cells in a DataBuffer.  But a DataBuffer is an implementation of the .NET Dictionary object, with is not Multi-Thread safe. 

So the largest use-case I can see for doing Parallel.ForEach() is not in a Finance BR, but in an Extender rule, where either
a) you want to go through a DataTable , returned from an SQL query , and process the rows in parallel
or
b) you want to go through a list of Data Units, (or list of Entities for example) , and for each data unit, execute a CustomFinanceBusinessRule in parallel for these data units.

Here's an example on how you would process a DataTable, processing multiple rows in parallel:

* Note : You would need to add the line:
Imports System.Threading.Tasks
to your BR

Dim strSQL As String = "SELECT * FROM <mytable>"
Dim dbConnApp As DbConnInfoApp = BRApi.Database.CreateApplicationDbConnInfo(si)
Using myTable As DataTable = BRApi.Database.ExecuteSql(dbConnApp, strSQL, False)
	Dim myOptions As ParallelOptions = New ParallelOptions() With { .MaxDegreeOfParallelism = Environment.ProcessorCount}
	Parallel.ForEach(myTable.AsEnumerable(), myOptions, Sub(currentRow As DataRow)
                                               Me.ProcessRowParallel(si, currentRow)
                                           End Sub)
End Using

Please read the whole thread here: https://community.onestreamsoftware.com/t5/Rules/How-to-speed-up-force-calculate-step/m-p/14706