Month: June 2017

Platform Cache

Introduction

In this blog post, I am going to explain “Platform Cache ” and how you are going to use. You may use many ways to improve your pages to run quickly by using custom settings and view states reduce technicians and so on.  But with new platform cache, you can store Salesforce session and org data for later access and applications can run faster because they store reusable data in memory.

How does Platform Cache work?

Platform Cache uses local cache and a least recently used (LRU) algorithm to improve performance.The local cache is the application server’s in-memory container that the client interacts with during a request. Cache operations don’t interact with the caching layer directly but instead interact with the local cache.For session cache, all cached items are loaded into local cache upon the first request. All subsequent interactions use the local cache. Similarly, an org cache gets operation retrieves a value from the caching layer and stores it in the local cache. Subsequent requests for this value are retrieved from the local cache. Platform Cache uses an LRU algorithm to evict keys from the cache. When cache limits are reached, keys are evicted until the cache is reduced to 100-percent capacity. If session cache is used, the system removes cache evenly from all existing session cache instances. The local cache also uses an LRU algorithm. When the maximum local cache size for a partition is reached, the least recently used items are evicted from the local cache

 Types Of Platform Cache: –

Platform cache supports two types of caches

  • Session cache—Stores data for individual user sessions. For example, in an app that finds customers within specified territories, the calculations that run while users browse different locations on a map are reused.

    Session cache lives alongside a user session. The maximum life of a session is eight hours. Session cache expires when its specified time-to-live (ttlsecs value) is reached or when the session expires after eight hours, whichever comes first.

  • Org cache—Stores data that any user in an org reuses. For example, the contents of navigation bars that dynamically display menu items based on user profile are reused.

    Unlike session cache, the org cache is accessible across sessions, requests, and org users and profiles. Org cache expires when its specified time-to-live (ttlsecs value) is reached.

Distribute the cache with Partitions

Partitions allow you to improve the performance by distributing cache space in the way that works best for your applications. after setting up the partitions you can add, access, and remove data from them using the Platform Cache Apex API.In order to use Platform Cache, create at least one partition. Each partition has one session cache and one org cache segment and you can allocate separate capacity to each segment. Session cache can be used to store data for individual user sessions, and the org cache is for data that any users in an org can access. You can distribute your org’s cache space across any number of partitions. Session and org cache allocations can be zero, or five or greater, and they must be whole numbers. The sum of all partition allocations, including the default partition, equals the Platform Cache total allocation. The total allocated capacity of all cache segments must be less than or equal to the org’s overall capacity.

After you set up partitions, you can use Apex code to perform cache operations on a partition. For example, use the Cache.SessionPartition and Cache.OrgPartition classes to put, retrieve, or remove values from a specific partition’s cache. Use Cache.Session and Cache.Org to get a partition or perform cache operations by using a fully qualified key.

To access the Partition tool in Setup, enter Platform Cache in the Quick Find box, then select Platform Cache. Click new Platform Cache Partition . each Partition should have a session Cache and org Cache. enter Partition name and label as “partition”

PC1

 

Handling Session cache

Use the Cache.Session and Cache.SessionPartition classes to manage values in the session cache. To manage values in any partition, use the methods in the Cache.Session class. If you’re managing cache values in one partition, use the Cache.SessionPartition methods instead.

 

If you’re managing cache values in one partition, use the Cache.SessionPartition methods instead. After the partition object is obtained, the process of adding and retrieving cache values is similar to using the Cache.Session methods. The Cache.SessionPartition methods are easier to use because you specify only the key name without the namespace and partition prefix.

 

 

Handling Org Cache

Use the Cache.Org and Cache.OrgPartition classes to manage values in the org cache. To manage values in any partition, use the methods in the Cache.Org class. If you’re managing cache values in one partition, use the Cache.OrgPartitionmethods instead.

 

If you’re managing cache values in one partition, use the Cache.OrgPartition methods instead. After the partition object is obtained, the process of adding and retrieving cache values is similar to using the Cache.Org methods. The Cache.OrgPartition methods are easier to use because you specify only the key name without the namespace and partition prefix.

 

Diagnose Platform cache

Cache diagnoses will provide the information about how much cache is used.The Diagnostics page provides valuable information, including the capacity usage, keys, and serialized and compressed sizes of the cached items. The session cache and org cache have separate diagnostics pages. The session cache diagnostics are per session, and they don’t provide insight across all active sessions.

Here is the simple code that used to store and retrieve the conversion exchange rates from the web services. Simple it checks the key is present in the Cache, it is going to retrieve the values from the platform chance otherwise it will store the values in the cache. so that you no need to make Webservice call even time to get the real time conversion rates

 

Considerations of platform cache and best practices 

  • Cache isn’t persisted. and there is no guaranty on data lost.Make sure you should handle the data loss properly. You can use CacheBuilder to handle the data losses.
  • Decided what type of data access you need like Concurrent vs serial retrieve and update. Org cache supports concurrent reads and writes across multiple simultaneous Apex transactions
  • think how to handle cache misses like Using CacheBuiler or you can use your own retrieval or update cache handling
  • Not all the data need to be stored in the cache. Including more data in the cache may impact performance. In case if you need to store the bulk data, split and store into multiple keys
  • Use the cache to store static data or data that doesn’t change often rather than changing the data very often

 

 

 

 

 

 

 

Platform Events in Salesforce

Introduction

In this blog post, I am going to explain about platform events a new feature generally available from Summer ’17 release as part of the “Enterprise Message Platform” which provide event driven architecture.

Let’s talk about Event Driven Architecture 

Salesforce event-driven architecture is consists of event producers, event consumers, and channels.  Platform events simplify the process of communicating changes and responding to events. Publishers and subscribers communicate with each other through events. One or more subscribers can listen to the same event and carry out actions .with an Event-driven architecture each service publishes an event whenever it updates or creates a data. Other services can subscribe to events.It enables an application to maintain data consistency across multiple services without using distributed transactions.  Let us take an example of order management. When the Order management app creates an Order in a pending state and publishes an OrderCreated event.The Customer Service receives the event and attempts to process an Order. It then publishes an OrderUpdate event.Then OrderUpdate Service receives the event from the changes the state of the order to either approved or canceled or fulfilled.The following  diagram show the event driven architect

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Terminology 

Event
A change in state that is meaningful in a business process. For example, a placement o of an order is a meaningful event because the order fulfillment center requires notification to process the order.
Event Notifier 
A message that contains data about the event. Also known as an event notification.
Event producer
The publisher of an event message over a channel.
Channel
A conduit in which an event producer transmits a message. Event consumers subscribe to the channel to receive messages.
Event consumer
A subscriber to a channel that receives messages from the channel. A change in state that is meaningful in a business process.

Looks like Streaming API, But Really not 

But when you overlook at Platform events it makes similar to Streaming API and most of the futures including the replayID and durability but below makes the difference between with streaming API.

  • Platform  events are special kinds of entity similar to custom object custom object
  • You can publish and consume platform events by using Apex or a REST API or SOAP API. Platform events integrate with the Salesforce platform through Apex triggers. Triggers are the event consumers on the Salesforce platform that listen to event messages.Unlike custom objects, you can’t update or delete event records. You also can’t view event records in the Salesforce user interface, and platform events don’t have page layouts. When you delete a platform event definition, it’s permanently deleted.
  • Platform events may be published using declarative tools (Process Builder)
  • platform events can also be subscribed to using APEX  or decoratively process builder  and flows

Another major,off-course really impressive one is you can publish changes from apex trigger and you can consume from apex trigger trigger

Publishing and subscribing Platform events 

Publishing and subscribing the platform event are more flexible. You can publish event messages from a Force.com app or an external app using Apex or Salesforce APIs and you can subscribe from the Salesforce or external apps or use long polling with cometD as well.

Let’s take an Example:- 

Now I am going to explain step by step to set up, publish and consume events. What we are going to do it Employee Onboarding Process. Now Once an external app publishes the events, we are going to create an account and when Salesforce publish onboarding events another system is going to receive the platform events.

1: – Define a Platform event


You can define platform event similar like custom object, go to setup –> develope –> Platform events –> create new platform events as shown below.

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By seeing it looks like custom objects but here are the few major considerations.

  • Platform event is appended the __e suffix for API name of the event.
  • you can’t query Platform events through SOQL or SOSL.
  •  you can’t use Platform in reports, list views, and search.
  •  published platform events can’t be rolled back.
  • e methods aren’t supported with platform events.
  • All platform event fields are read-only by default
  • Platform events don’t have an associated tab
  • Only after insert Triggers Are Supported
  • You can access platform events both through API and declaratively
  • You can control platform events though Profiles and permissions

2: – Publishing Platform Events

You can publish events using an Apex method or with declarative tools, such as Process Builder or the Cloud Flow Designer or you can publish events using Salesforce API. we are going to seeing all the ways how to publish the platform events.

Publish Using Apex

you can publish platform events by using apex trigger or execute anonymously and batch Apex etc.But here I am going to publish by using Apex triggers. A trigger processes platform event notifications sequentially in the order they’re received and trigger runs in its own process asynchronously and isn’t part of the transaction that published the event.

 

 Now if you can see, Salesforce has a special class to publish the platform events EventBus which is having methods publish method. once the event is published you can consume the events from the channel

Publish Using Process Builder 

You can publish platform events using the declarative tools like process builders and flows. Here is the image shows the platform events insert by using process builder.

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Publish Events by Using API

 

Now I am going to see another way of publishing events from API. I am going to use the workbench to publish the events.
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3: – Subscribe for Platform events from the channel

You can now subscribe to the platform events from the Platform events object trigger which is created in step 1. Here is the sample trigger show how you can handle the subscribed events. Here simply I am creating new accounts from the platform even but you can implement your own business logic to update the data .

 

Here is the simple visual force page that consumes the platform events which you published. This page is built on cometD.
you can consume the platform events by using this  URI /event/Employee_On_boarding__e and the Complete code is here below.

Key points


1 . Platform events are executed under ” Automated Process entity.” So you have set Automated Process in debug logs
2. You can control the Platform events on Profile and permission sets
3.You can see all the platform events that are subscribed under Platform events objects.
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4. Platform events have lifecycles state like Running, Ideal, Suspended,, Error, Expired
5.Platform events are having retry mechanism.