Hi Chris a BP queue is by default 'first come first served', and it contains logic to ensure that a queue item cannot be locked by multiple instances of a process. So if your design requirement is 'all instances should work whichever item is next until there are no more items', then you don't need to do anything. Just use Get Next Item followed by a Decision to test if an item was received or not (ie [Item ID]<>"").
You may have a project where the requirement is to work items in a particular order, and you can achieve that by applying tags when adding items to the queue and then using the Tag Filter input parameter in Get Next Item. That way you do things like 'work all items tagged as Joint Account first, the do all Loan Accounts, then Savings Accounts, then Credit Card Accounts.
Another option is to assign a Priority number when adding items, eg Joint=1, Loan=2, Savings=3, Card=4. Then Get Next Item will automatically give you all the P1s first, then all the P2s etc.
When considering how an automation will run in parallel, think whether there are any steps that you don't want to be replicated across all machines. Typically this will be when filling the queue, because you don't want every instance loading the same input data and creating duplicate queue items. This is where Environment Locks come in. Think of an EL as a permission token, where all instances compete for a single token, and the winner of the token is the one allowed to perform the 'special action' (eg load the queue) and the losers have to take a different direction (eg wait until the queue is loaded). For example:
- 10 instances of the process start at the same time
- All compete for the environment lock
- 1 instance wins and 9 lose out
- The winner 'goes right' and loads the queue, the losers 'go left' and enter a waiting loop
- After loading the queue, the winner releases the lock and proceeds to Get Next Item
- The losers detect that the lock is available and proceed to Get Next item
- All 10 instances work in parallel until the queue is depleted
------------------------------
John Carter
Blue Prism
------------------------------
