Flow Bulkification and Apex

For the past few weeks I’ve been working on a side project at work which involves working with Flow from Apex. I’ve learned a few interesting things that I might blog about in future but today I want to write about one annoyance, that I was aware of before, but which has now come to the fore. There is an Idea to upvote here.

There is also this more limited Idea that requests a new type of Flow specifically to allow bulkfied offload to Flow from Apex triggers. This is too limited as we will see below.

My Apex code is calling a Flow for every record that it is processing. Normally programmers on the Salesforce platform want to bulkfiy everything. We’d not like to write code like this

List<SObject> records = …;
for (SObject record: records) {
  doSomethingWithARecord(record);
}

Especially if do something involves any more SOQL or DML. This sort of thing will almost certainly scale poorly and result in governor limits exceptions. We’d like to do something like

List<SObject> records = …;
doSomethingWithRecords(records);

Where we do any DML or SOQL once acting on all the records together. This will be much more efficient as each time we make a call to the database the app server our code is running on has to talk over the network to the database server which will take some time to respond. Much better to do that once rather than 200 times!

However when calling out to Flow this is unfortunately impossible. We have the createInterview method or, if the API name of the Flow is know at build time, the direct Flow.Interview.<FlowName> method. In each case these methods create a single Flow Interview instance which takes a single set of input variables. We cannot create, or start these interviews in bulk.

We can still loop and create and start the Flow Interviews singly but as above this might be inefficient, especially if the Flow is doing SOQL or DML operations. Another option would be to pass the Flow a list of records instead of a single record and have the Flow loop. If the Flow is well constructed this could be pretty efficient but anything in the loop in the Flow won’t be bulkfiied. The Flow designer will have to take care to use collection variables to build lists to operate on in bulk, and many won’t.

However Flow does support cross interview bulkfiication. When this is triggered, for example when multiple interviews are started for a record triggered flow, actions in the interviews are actually run as a single action across all the Interview instances allow it to act in bulk. This allows the Flow author to design natural single record Flows without worrying about bulkfiication. Most Flow authors thing and build this way.

In an ideal world we could access this from Apex. We should be able to create/start multiple interviews in parallel and have them bulkfiied by the platform. Please vote for the Idea so as this might happen.