Saturday 2 March 2024

Hands on with Prompt Builder

Image generated by DALL-E 3 based on a prompt created by Bob Buzzard


Unless you've been living under a rock, you'll have seen some big news from Salesforce in the Generative AI space this week (29th Feb 2024, for future readers) - Prompt Builder is Generally Available and Copilot is in Beta. 

I've been lucky enough to get my hands on both of these new features and have an initial dig around, so continue reading to find out how I got on with Prompt Builder. Like it's General Availability, my hands on experience with Copilot is coming soon!


Setting up Prompt Builder is very straightforward:

  1. Navigate to Setup -> Einstein Generative AI -> Einstein Setup and toggle it on
  2. Assign the Prompt Builder Manager/User permission sets
  3. Reload Setup, then navigate to Setup -> Einstein Generative AI -> Prompt Builder and start prompting.

Creating Prompts

I've mostly played with the Sales Emails prompts, aside from my Copilot experiments (see below). My initial use case was follow up emails for attendees of one of my World Famous Release Webinars, so I created a new custom object of Webinar and added a few fields that I wanted to pull into my prompt - the usual name and description, but also a couple of fields to capture the URLs of additional resources I wanted to send. I also added a Call to Action - this is a field to capture what I was hoping the attendees would do after attending - try out a couple of the features, for example.

Once I'd added the Webinar custom object, it didn't appear immediately in the prompt builder as a selectable Related Object. After checking the docs to make sure I hadn't missed a checkbox to make it available, I decided it must just be a timing thing - maybe the objects needed reindexing or the like. Then
I found that I couldn't create any prompts for a period of time - not sure how long, but it felt like 30-40 minutes - during that time the Related Object selector wouldn't populate at all. Then clearly whatever had been happening in the background finished, and I could select my new Webinar object.

My prompt is loosely based on the standard follow up email, but includes specific instructions and fields related to my webinar :

You are a Sales Executive and your name is {!$Input:Sender.Name} from an organization called {!$Input:Sender.CompanyName}. Your prospect is {!$Input:Recipient.Name}, who is the {!$Input:Recipient.Title}, from the company called {!$Input:Recipient.Company}.Your prospect {!$Input:Recipient.Name} attended a Salesforce release webinar that your company hosted.
When I ask you to generate a follow-up email to your prospect you must strictly follow my instructions below.
Instructions: """
The salutation must only contain the recipient's first name.
You must strictly not use "I hope this email finds you well" ,"I hope this email finds you doing well", or any other variation that expresses interest in the recipient's well-being to open the email.
Create a follow-up email conveying that you are following up on their attendance of {!$Input:Webinar__c.Name} to see if they need any additional information or support.
Mention the webinar, the number of attendees from {!$Input:Webinar__c.Attendee_Count__c} and include a summary of the {!$Input:Webinar__c.Description__c}. Express the hope that it was useful for them and that they will follow the call to action identified at {!$Input:Webinar__c.Call_to_Action__c}
End the email with details of the two additional resources that are available : {!$Input:Webinar__c.Resource_1__c} , which is {!$Input:Webinar__c.Resource_1_Detail__c} and {!$Input:Webinar__c.Resource_2__c}, which is {!$Input:Webinar__c.Resource_2_Detail__c}
Finish by indirectly encouraging your prospect {!$Input:Recipient.Name} to respond to your email by asking them if they need any further information, have questions or require assistance.
Generate a subject line that can increase open rate using words and content related to the email body.
Now generate the follow-up email to your prospect.

Grounding the Prompt

I then provide a couple of sample records to test the prompt out. The Lead record is one that came with the org and will probably be familiar to anyone that has used a Salesforce Developer Edition before - Lauren Bailey from Omega, Inc. The webinar record is as follows:

The resolution section is useful when you are grounding the prompt with a number of inputs - it shows the expanded merge fields so you can see exactly what you'll be sending the AI model (although sensitive data will be masked by the Einstein Trust Layer, obviously):
You are a Sales Executive and your name is Keir Bowden from an organization called Credera. Your prospect is Lauren Bailey, who is the Director of Services, from the company called Omega,Inc.Your prospect Lauren Bailey attended a Salesforce release webinar that your company hosted.

When I ask you to generate a follow-up email to your prospect you must strictly follow my instructions below.

Instructions: """
The salutation must only contain the recipient's first name.
You must strictly not use "I hope this email finds you well" ,"I hope this email finds you doing well", or any other variation that expresses interest in the recipient's well-being to open the email.

Create a follow-up email conveying that you are following up on their attendance of Spring 24 Release Webinar to see if they need any additional information or support.

Mention the webinar, the number of attendees from 150 and include a summary of the Learn about the key new features and enhancements in the Spring 24 release of Salesforce.. Express the hope that it was useful for them and that they will follow the call to action identified at Enable dynamic forms and add related objects to your records home pages.

End the email with details of the two additional resources that are available : , which is Salesforce Release Notes and, which is Webinar Recording

Finish by indirectly encouraging your prospect Lauren Bailey to respond to your email by asking them if they need any further information, have questions or require assistance.

Generate a subject line that can increase open rate using words and content related to the email body.

Now generate the follow-up email to your prospect.
I found that my original calls to action, even though they looked good in the record, didn't work very well when included in the prompt, so always have a look at the resolution the first couple of times.

The Response

The response from OpenAI GPT 3.5 Turbo was pretty good I thought, although maybe a little brusque - I'll probably rework it to a slightly more chatty version, but it's a great start for a small amount of work:
Enhance Your Salesforce Experience with Spring 24 Release Insights

Hello Lauren,

I trust you found the Spring 24 Release Webinar insightful. With 150 attendees, we hope you gained valuable insights into the key new features and enhancements in the Salesforce Spring 24 release. The webinar highlighted how to enable dynamic forms and add related objects to your records home pages.

For further exploration, two additional resources are available:
- Salesforce Release Notes:
- Webinar Recording:

Should you require any additional information, have questions, or need assistance, please feel free to reach out.

Best regards,
Keir Bowden

Grounding with Apex/Flow

I can see I'll be doing a lot of grounding with pro or low code - if I'm sending an email regarding a product I'll probably want to include a rate card and maybe some contractual information for example.  Grounding with Flow is very straightforward, and once you choose a Template Triggered Prompt Flow and pick the Sales Emails capability, there's a nice screen to define the object types you are using :

Apex is a little different - you define a class with an invocable method that defines the capability, then define Request and Response inner classes to manage the input and output parameters:

@InvocableMethod(label='Price for Lead' description='Gets the price of a product for a lead' 
public static List<Response> getProductStandardPrices(List<Request> requests)  
        --- --- ---
public class Request {
    public User sender;

    public Lead recipient;

    public Webinar__c relatedObject;

public class Response {
    public String Prompt;

Apex is also a little different in that I couldn't get it to work! Even after copy/pasting the example in the Salesforce help, it wouldn't show up in the Resources selector. I'm sure this will be resolved soon, and as Prompt Builder has been one of Salesforce's more rapid features to go GA, I'm okay with their being a few glitches. As I've written before, I'll take a bit of additional effort tracking down issues if it means I get my hands on things earlier.

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Sunday 25 February 2024

Zip Handling in Apex, Spring '24 Developer Preview

Image generated by DALL-E 3, based on a prompt by Bob Buzzard


The Spring '24 release of Salesforce had some great new features and improvements, but for me some of the Beta/Developer Preview features were more interesting - for example the scratch org snapshots beta that I wrote about a few weeks ago.

I've been developing on the Salesforce platform for close to 16 years now, and I've lost count of the number of different approaches that I've taken to handle zip files. Sometimes on the server, sometimes on the client in JavaScript, but always using custom solutions that didn't perform fantastically well. The new functionality that is native to Apex won't solve this problem - governor limits still apply - that fact that it isn't implemented in Apex itself should mean that a little more processing can be wrung out of the transaction.

Trying it Out

This is a departure from previous developer preview functionality that I've tried in the past, as it's available in scratch orgs only. I'm onside with this approach as it feels like it will allow the Apex development team to be more agile and give us access to changes earlier. Anything that does go awry will disappear in a maximum of 30 days, so there won't be loads of developer editions left behind needing to be patched up. I'll take a bit of additional effort tracking down issues if it means I get my hands on things earlier.

You need to enable support for zip file processing via the features property in your scratch org definition, specifying ZipSupportInApex :

  "features": ["EnableSetPasswordInApi", "ZipSupportInApex"],

Then create a new scratch org and you are off to the races.

What Worked

Creating a zip file and then extracting it works great - I did this through some execute anonymous Apex and was pleasantly surprised there were no further hoops to jump through. As this is in developer preview I didn't expend a huge amount of effort, just adding a single entry created from a String via a Blob:

public void SimpleZip()
    Compression.ZipWriter writer=new Compression.ZipWriter();
    writer.addEntry('zs.csv', Blob.valueOf('Name, Title\nKeir Bowden, CEO'));
    Blob zipFile=writer.getArchive();

    ContentVersion contentVer = new ContentVersion(
        VersionData =zipFile,
        Title = '',
        Description = 'Zip Sample',
        PathOnClient = '/'

    insert contentVer;

Once I'd done this, I could see the zip and download it to extract files:

And to extract the file from the zip and debug the contents in Apex :

public void SimpleExtract()
    ContentVersion contentVer=[select Id, VersionData, Title, Description, PathOnClient
                                from ContentVersion
                                where Title=''];

    Blob zipBody = contentVer.VersionData;
    Compression.ZipReader reader = new Compression.ZipReader(zipBody);
    Compression.ZipEntry csvEntry = reader.getEntry('zs.csv');
    Blob csv = reader.extract(csvEntry);

    System.debug('CSV body = ' + csv.toString());

Gave me the contents of the file that I'd created from my String :

What Didn't Work

The demo that I was actually trying to put together was the ability to choose a zip file from the content library and inspect the contents via the UI. Selecting the file was all well and good, but once I tried to extract the details of the files and wrap them in an inner class, I was out of luck.

In case it was something about my processing of the entries, I tried just debugging them :
public static List<Entry> GetZipEntries(Id contentVersionId)
    List<Entry> entries=new List<Entry>();
        ContentVersion contentVer=[select Id, VersionData, Title, Description, PathOnClient
                                    from ContentVersion
                                    where Id=:contentVersionId];

        Blob zipBody = contentVer.VersionData;
        Compression.ZipReader reader = new Compression.ZipReader(zipBody);
        for (Compression.ZipEntry entry : reader.getEntries())
            System.debug('Entry = ' + entry.getName());
    catch (Exception e)

    return entries;
but this failed in the same, odd way. No exceptions, no errors, just an exit of the server side call when I invoked ZipReader.getZipEntries().

In case it was something Lightning Components related I dusted off my Visualforce skills and tried a custom controller :
public List<Entry> getEntries()
    if (null==this.entries)
        entries=new List<Entry>();
        String cvId=ApexPages.currentPage().getParameters().get('cvid');
        System.debug('Id = ' + cvId);
        ContentVersion contentVer=[select Id, VersionData, Title, Description, PathOnClient
                                    from ContentVersion
                                    where Id=:cvId];

        Blob zipBody = contentVer.VersionData;
        Compression.ZipReader reader = new Compression.ZipReader(zipBody);
        for (Compression.ZipEntry zipEntry : reader.getEntries()) 
            System.debug('Processing entry');
            Entry entry=new Entry();

    return entries;
This was slightly more successful, in that it very occasionally showed the list of entries after a hard reload of the page. Most of the time though, it behaved the same and just gave up when I executed ZipReader.getEntries().

Just in case it was something about my zip file, which was an old bootstrap library I had lying around, I copied the same code into a new class and invoked that using execute anonymous.

That worked fine:

So it does appear there is an issue accessing the contents of a zip file in a transaction that originated from a custom UI, or something along those lines anyway. I couldn't find anything in the docs to indicate I shouldn't be trying this, but it is in developer preview so I'd expect a few glitches. As a wise man once said, "I'll take a bit of additional effort tracking down issues if it means I get my hands on things earlier.". 

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Sunday 11 February 2024

Apex Null Coalescing Operator

Image generated by DALL-E 3 based on about 10 prompts by Bob Buzzard


The Spring 24 release of Salesforce bring a new operator to Apex - the null coalescing operator. It makes me very happy when these kinds of operators make their way to Apex, as it feels like we're a real programming language!

The null coalescing operator consists of an operand, two question marks, and another operand:

  operand1 ?? operand2

When the expressions is evaluated, if operand 1 is not null that will be the result, otherwise operand2 will be the result. Note that this isn't a mechanism for avoiding a null result, as if operand1 is null, operand2 will be the result even if it is null.

Using the Operator

The key use case for the null coalescing operator is removing explicit, and possibly lengthy, null checks. The obvious one is falling back on a default value, so instead of :

public List<Contact> getContactsForAccount(Account account)
    List<Contact> contacts=contactsForAccount.get(account.Id);

    if (null==contacts)
        contacts=new List<Contact>();

    return contacts;

we can write:

public List<Contact> getContactsForAccountNew(Account account)
    List<Contact> contacts=contactsForAccount.get(account.Id) ??
                            new List<Contact>();

    return contacts;

Much more compact, but that's not all - there's another aspect to this that is good and bad in equal measure. As there is now a single line evaluating the list of contacts, a single test will give 100% coverage of the line regardless of whether the first or second operand is as the result. For some developers this is good - one less scenario needed for test coverage. For others (including me) this is bad - if both scenarios aren't tested then we don't know how it will behave when the missing scenario happens in production.

Actually there's a third aspect to this too - the right hand operand isn't evaluated if the left hand is non-null, so it's efficient and devoid of unexpected side effects.

You can also chain them. so if you have five potential candidates for an opportunity value to return, you can write:

   Opportunity opp=opp1 ?? opp2 ?? opp3 ?? opp4 ?? opp5;

Safe in the knowledge that the first non-null value will be used. 

You also don't have to use objects or primitives as the operands, but watch out for the loss of clarity if you start to put too much working into a single expression.  For example, I don't think this is the clearest way to extract a title given an Id that might refer to a Contact or a Lead:

return [select Title from Contact where Email=:email][0].Title ??
       [select Title from Lead where Email=:email limit 1].Title ??
       'No contact/lead found matching email';Al

Always think about those that come after you!

Use to pull a collection from a map or add the new collection in if it's not present. Instead of

Apples with Apples

The operands must both be the same type, so you can't have the first operand being a Lead and the second being a Contact unless they can be converted to a common type  - e.g. an sObject. By the time you introduce casting though, I'd say you've lost most of the benefit due to some ugly code:

Contact contactCand=new Contact();
Lead leadCand;

String name = (String) ((sobject) leadCand ?? (sobject) contactCand).get('Name');

You can also compare operands that can be promoted to a common type by the compiler, for example if you have some inheritance at play:

public virtual class First
    public String name {get; set;}

public class Second extends First

First first=new First();
Second second=new Second();
String name=(first ?? second).name;

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Sunday 14 January 2024

Scratch Org Snapshots in Spring '24

Note: This feature is in beta in Spring '24. Like all other betas, this functionality may never go GA and may disappear at any time. Caveat emptor.

Image generated by DALL-E 3 based on a prompt by Bob Buzzard


The Spring '24 release of Salesforce moves the scratch org snapshot functionality into beta. I've been waiting to get my hands on this and so far it hasn't disappointed.

Whenever we get new features of this nature, I like to reflect on how far we've come in Salesforce land. In this case I was testing with the codebase of our BrightMEDIA accelerator, and when we started building this in mid-2014 (aka nearly a decade ago), we typically allowed a week to get a new developer set up. We had to spin up a Developer Edition, raise a bunch of tickets to get various features enabled and increase the Apex character limit, install a number of packages, carry out a number of manual setup steps,  deploy the code and assign permission sets. For whatever reason, no two Developer Editions appeared to have the same setup, so typically the deployment was an iterative process where we discovered what was missing or off instead of on by default. Then they'd go through and set up some standing data to be able to work in the org. 

Fast forward to the end of 2023 and I have a node script that creates a scratch org, installs the packages, deploys the code, loads the standing data and produces a ready to go development environment in around 30 minutes. I'm always interested in speeding things up though!

Creating a Snapshot

Thanks to a pre-release environment that I've also had for a decade, I have a pre-release dev hub which meant I could enable the beta before the Spring '24 release goes live. Then I assigned myself the appropriate object permissions for Org Snapshots and I was ready to create. 

I set up my scratch org using my existing script, which creates an org with the following applied:

  • Four managed packages
  • Approximately 9,000 metadata components
  • Approximately 2,000 records
Creating a snapshot of this org took 11 minutes, which I must admit was quite a bit faster than I was expecting.

Using the Snapshot

This started off with a bit of a challenge, in that attempting to use the snapshot kept giving the error that the snapshot wasn't Active, but listing the Dev Hub snapshots showed that it was indeed Active. I spent a while searching through the CLI Github issues list and the snapshot pilot Trailblazer group, but it seemed like I was the lucky one who got to experience this first. This was quite soon after the pre-release had gone live, so I figured it might be a simple bug and played the waiting game.

About 7 hours later my masterful inactivity was rewarded, as my snapshot sprang to life and I was able to run the commend to create an org from it. In fairness, it might have started working 10 minutes later, but it was around 7 hours later I had the time to try it out again.

The even better news was that creating a scratch org from the snapshot took 6 minutes - an 80% saving on the 30 minute creation time for my script. The org was flawless too - all the metadata and data was there.

The End of Sandboxes?

So does this mean that we can all create scratch org snapshots rather than sandboxes going forward? They even contain data, so maybe we can do away with full or partial copy sandboxes too.  I don't think so, for a few reasons.


Scratch orgs and org snapshots, have a 30 day lifespan. From a developer perspective this is fine - we treat these orgs and disposable and typically create a fresh one when we start a new piece of work. That isn't necessarily the case for orgs used for training, QA, integration testing or testing against a new release. It's particularly unsuitable for pre-production environments which mirror production - imagine having to recreate all your test integrations at the start of every month!


Scratch orgs and org snapshots are limited to 200Mb of data. Again, probably fine for many development tasks, but again likely to be too small for training, pre-production and test environments that are indicative of production. 


Sandboxes replicate your production org licenses, so all of your users can have access. Scratch orgs are a much more restrictively licensed, usually somewhere between 1 and 10 seats per feature. When we were adding community (now Experience Cloud) features to BrightMEDIA, we had the princely sum of 1 partner community license available in our scratch orgs - you'd have to be quite brave to promote to production with that kind of limitation on your testing!

Completeness of Version Controlled Metadata

This is where developer/developer pro sandboxes will retain their usefulness once scratch org snapshots are live. Some organisations with large, mature Salesforce orgs won't have all their metadata in version control, because why would they invest the time and money to do that when they don't need to. They'll likely have Apex, flows, lightning components, and maybe some second generation packages in version control, but things like sharing rules, report and dashboard folders, duplicate rules that are managed by administrators probably won't. Yes this is a sweeping generalisation, but you get the general idea. Being able to create a guaranteed replication of production to work in will be an important capability for years to to come in my view.  That said, they'll probably become less used as time goes on and maybe scratch org snapshots get longer lifespans.

So not a sandbox killer, but that was never the intention. For those of us with a very source-centric development approach however, this is another great addition to the developer toolbelt.

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Sunday 7 January 2024

Breaking Batch

Image generated by DALL-E 3 from a prompt by Bob Buzzard


In my last blog post (A Tale of Two Contains Methods) I mentioned that I'd spent quite a bit of December taking part in Advent of Code.  Each day there were two challenges - a (relatively) straightforward one, that could potentially be brute forced, and an extended version where brute forcing would take days so using the a more thoughtful approach was required. As I was tackling these challenges using Apex, brute forcing wasn't really an option, so my solution typically involved building structures of complex objects in memory in order to be able to process them quickly. Pretty much every extended version required batch Apex to handle the volumes, and in a few cases the (relatively) straightforward one did too.

The combination of the complex object structure and batch Apex threw up some interesting errors, so I decided to blog about one of these. A couple of things to note:
  • This isn't a moan about batch Apex - I was using it in a way that I'm pretty sure it wasn't intended for, and there was a simple workaround
  • By complex object I just mean one that is made up of primitives, simple(r) objects and collections - it doesn't mean it was a particularly difficult structure to comprehend or change.

The Challenge

(Some of the challenge detail has been removed for clarity - you can see it in its full glory here)
Part 1 of the challenge in question was around bricks of varying length in a 3-dimensional structure (essentially a large cube) that had landed on top of each other like a weird Jenga puzzle. Based on the starting coordinate and dimensions of each brick, I needed to figure out how the bricks were supported in the structure. 

The approach I took was to represent a brick as an object and hold two associated collections for each Brick instance:
  • Supporters - these are the Bricks that are directly beneath this Brick and in contact with it.
  • Supporting - these are the Bricks that this brick is directly beneath and supporting. 
The answer I had to calculate to complete the challenge was number of bricks that I could remove without causing any other bricks to fall. This could be accomplished by iterating the bricks and adding up all of those where all of the Supporting bricks are also supported by others. 

Part 2 was to find sum of the bricks that would fall if each of the bricks were removed. With the structure that I had in place, this was actually quite simple. I iterated the bricks, found all of the Supporting entries where that brick was the only Supporter, and then found all of their Supporting entries where they were the only Supporter and so on until I reached the end. This would definitely need batch Apex though, as there were 1,500 bricks in the actual challenge input.

Each challenge includes a small example with the workings and answers - 6 bricks in this case - so I was  able to test my batch Apex before executing with the larger volume of data.

My Brick class was as follows:
public class Brick
    public String brickNo;
    public Point3d startPoint;
    public Point3d endPoint;
    public Integer width;
    public Integer depth;
    public Integer height;
    public Set<Brick> supporters=new Set<Brick>();
    public Set<Brick> supporting=new Set<Brick>();
    public Integer totalSupporters=0;
The start method of the Batch class converted the input into a collection of Bricks and then returned a collection of Integers, one per Brick. I implemented Database.Stateful so that the collection of Bricks was available across each execute method, and then processed the Bricks who's brickNo appeared in the scope. Essentially I'd broken up my iteration of the Bricks across a number of transactions, while ensuring I only had to build the Bricks structure once at the start.

When I ran this with the example, it worked fine and gave me the correct answer. 

The Problem

I then fired it off with the (much larger) challenge input, and was initially pleased to see that I was able to build the in-memory structure without running into any issues around heap or CPU. Sadly this pleasant sensation was short lived, as the first batch that executed generated the following output:

Based on the debug that I had in the class, it was clear that the batch job was failing before it was getting to any of my code. After some binary chop style debugging, where retried the batch with various parts of the code commented out, it turned out that the issue was my collections:
    public Set<Brick> supporters;
    public Set<Brick> supporting;

As I already had the full collection of Bricks stored in a Map keyed by brickNo, turning these into sets of Strings and storing the brickNo rather than a reference to the Brick itself didn't need much in terms ot changes to the code, and allowed the batch to complete without issue.

So why were Sets of Strings okay by Sets of Bricks not? Once I was into a large cube with 1,500 bricks in it, it looked like the sets got pretty big. As the Bricks were stored in an instance variable, they were part of the state of the batch and thus de/serialised for each batch processed. Obviously I'm not privy to exactly how the batch processing in Apex works, but I'd imagine that serialising ended up with a pretty huge structure with a lot of repetition, as the same Brick instances were expanded many times as part of  the Supporters and Supporting collections. Deserialising this structure clearly proved too much, hence the internal error. 

In Conclusion

As mentioned earlier, this isn't intended to throw shade on batch Apex. Storing large collections of complex objects that contain collections of other complex objects so they can be accessed across transactions really isn't a valid use case. This kind of information belongs in the database rather than in the batch class, while Database.stateful is more appropriate for managing things like running totals.

This is one of the reasons that I really enjoyed taking on Advent of Code with Apex - I'm trying to solve problems that (a) I'd never encounter in a customer implementation and (b) the Salesforce platform is really not suited to handling.

This was also a lesson in the need to test with indicative data - everything worked fine with the small amount of test data I had available, but once I hit the real data the flaws were revealed!

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Thursday 28 December 2023

A Tale of Two Contains Methods

Image generated by DALL-E 3 from a prompt by Bob Buzzard 


Eagle-eyed regular readers of this blog may have noticed that I dropped away during the build up to Christmas this year, and there was a good reason for this. I was taking part in Advent of Code, having been introduced to it by our Credera brethren. A challenge a day for 25 days - two a day in fact, as if/when you solve the first, it gets tweaked to make it harder. 

I opted to use Apex to take on the challenges, which ensured that I couldn't brute force any solutions, and that I typically had to switch to a batch/asynchronous approach when I finally ran out of CPU or heap. This didn't always help by the way - a few times I had to give up after encountering variants of "the batch class is too large" error. A few other times I had to accept solving one challenge of the two when I couldn't figure out how to even start on the second!  I ended up with 39/50 successes though, which didn't seem like a bad return for a constrained language. It was extremely enjoyable, but be aware that this can easily soak up all of your spare time and more, and may not make you popular at home!

A common theme of the challenge was walking a route through a grid and keeping track of the tiles that I'd encountered before, usually with some additional information around which path I was following, the direction I'd moved in and how many steps I'd taken in a direction. If it was net new then I needed to add it to a collection, but I also needed to order the collection, as I was looking for the shortest or longest route possible, so they needed to end up in a List.

A Tale of Two Contains Methods

It was the best of methods, it was the worst of methods

One difference between Apex and some other languages I've worked with in the past is the contains method on the List class - this handy helper returns true if the list contains the element passed in to it. This saves me from either iterating the list each time I consider adding an element, or maintaining a separate "lookup" collection - typically a Set that matches the list and I'd check if the element was in there first.

I used the List contains method in my first attempt on one of the challenges, and found that I had to quickly go to batch apex. In order to walk the path I was carrying out a breadth-first search, adding every possible option for each step to a queue as a complex object, but always processing the shortest option first. Once the queue got to around 3,000 elements (complex objects), I found that I could only process a few of them before breaching the 60,000 millisecond CPU limit, and I was looking at an extremely large set of batches that would likely take multiple hours to complete.  After a bit of digging it looked like the check/add to the queue of steps wasn't scaling overly well, so I switched back to maintaining a separate lookup Set and using the Set contains method to determine if I'd seen it before. Once I did this, the CPU use dropped to the point where I could complete the whole thing in 2-3 batches, which I did.

I was somewhat taken aback by this, as I'd assumed that the List contains method would be using an efficient mechanism under the hood and would perform well regardless of the size of the list/complexity of the object. This turns out not to be the case, but that's really my fault for assuming - there's nothing in the docs to suggest that it will be doing anything of the sort.

Now that Advent of Code has completed, I've had the time to run some numbers on the CPU consumption of each of these contains methods (hence the witty title, with apologies to Charles Dickens of course), and present the results.

The Methodology

I have defined a (not particularly) complex object so that there's a bit of work involved to determine if another object matches it:

public class ContainsObject 
    public String stringRep;
    public Integer intRep;
    public Long square;
    public DateTime timestamp;
    public ContainsObject(Integer idx)

I then add two thousand of these to a List, checking each one to see if I've seen it before. The CPU consumed is captured for every 100 elements and gives the following results:

   Count            CPU

   0 - 100           76
 400 - 500           97
 900 -1000          169
1400 - 1500         460
1900 - 2000         582

from this I can deduce that there isn't anything particularly efficient going on under the hood - as the size of the List increases, so does the time taken to check and add 100 elements. In the 1900-2000 range the average is over 5ms per check/insert, which is quite a chunk for a couple of statements.

Switching to the List and lookup Set approach, I create a Set of the complex objects to mirror the contents of the List, but without any ordering, that I can use for the check part. If the element isn't present in the Set, I add it to both the Set and the List.

Executing this for the same number of complex objects gives:

   Count            CPU

   0 - 100           4
 400 - 500           6
 900 -1000           5
1400 - 1500          4
1900 - 2000          7

This is much more the kind of result I want to see - the performance isn't really changing regardless of the size of the Set, and while the final hundred takes slightly longer than the first hundred, the average is 0.07ms, which leaves me plenty of CPU to play with in the rest of the transaction.

No Downside?

As always, there's no such thing as a free lunch - the fact that I have to maintain another collection for speedy lookup does incur a heap penalty. It is a pretty cheap lunch though, as I'm only holding references to the objects stored in the List rather than copies, so the 2,000 entries in the Set consume another 8kb of heap. This feels like a pretty decent trade off to me, but if your transaction has plenty of spare CPU and is butting up against the heap limit, you'll likely feel different.

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Saturday 11 November 2023

OpenAI GPTs - Meet Bob Buzzard 2.0


During OpenAI DevDay, the concept of custom GPTs was launched - Chat GPT with a bunch of preset instructions to target a specific problem domain, additional capabilities such as browsing the web, and extra knowledge in terms of information that may not be available on the web. 

In order to create and use GPTs, you need to be a ChatGPT Plus subscriber at $20/month, although in the UK there's VAT to be added so it works out around £20/month. This also gives priority access to new features, the latest models and tools, faster response times and access even at peak times. I signed up just to try out GPTs though, as they looked like a world of fun.

The Replicant

My first custom GPT is my replicant - Bob Buzzard 2.0. A GPT that has been pointed at most of my public and some of my private information. Instructed to respond as I would, you can expect irreverent or sarcastic responses as the mood takes (AI) me. Obviously very focused on Salesforce, and keen on Apex code. 

Right now you'll need to be a ChatGPT Plus user to access custom GPTs, but if you are you can find Bob Buzzard 2.0 at :  Here's a snippet of a response from my digital twin regarding the impact of log messages on CPU - something I've investigated in detail in the past :

Creating GPTs

This is incredibly simple - you just navigate to the create page and tell it in natural language how you want it to behave, define the skills, point it at additional web sites or upload additional information. It's easy and requires no technical knowledge, which does make me wonder why they announced it at developer day given there's no development needed, but lets not tilt at that windmill.

A Couple of Warnings

First, remember that any private information that you upload to a GPT won't necessarily remain private. If you don't instruct your custom GPT to keep instructions and material private, it will happy share them on request. 

Second, I've given the replicant a mischievous side - from time to time it will just gainsay your original decisions when you ask for help with specific problems, maybe suggesting you have picked the wrong Salesforce technology, or telling you to bin it all off and use another vendor. Think of this as your reminder that a human should always be involved in any decision making based on advice from AI.

I'm Going to be Rich?

Something else that was announced at Developer Day was revenue sharing - if people use Bob Buzzard 2.0 I'll get a slice of the pie. So does this mean I'm going to be rich? Like always, almost certainly not. As you just click a button and answer questions to create a GPT, there will be millions of them before too long. They are so easy to create that something a service like Salesforce development advice, with the vast amount of content already in the public domain, will be extremely competitive - an extremely crowded marketplace of similar products means everybody earns nothing.

That said, I think this is something that genuine creatives will be able to earn with. Rather than having their work used to train models that are can then be used to produce highly derivative works for close to free, they can create their own GPT and at least stand a chance of getting paid. Whether the earnings will be worth it we don't yet know, although history suggests the platform providers will keep everything they can.