Transaction Cache

In-memory caching for the duration of a single transaction.

Overview

Transaction cache stores data in memory for the lifetime of a single Apex transaction. When the transaction completes, the cache is cleared.

CacheManager.ApexTransaction

Characteristics

• Lifetime: Single transaction only
• Scope: Current transaction
• Storage: In-memory (heap)
• Persistence: Not persistent
• Sharing: Not shared across transactions

When to Use

Use transaction cache when you need to:

• Avoid redundant SOQL queries within a transaction
• Cache expensive calculations
• Store temporary data during processing
• Share data between methods in the same transaction

Basic Usage

// Store in cache
CacheManager.ApexTransaction.put('userId', currentUser);

// Retrieve from cache
User user = (User) CacheManager.ApexTransaction.get('userId');

// Check existence
if (CacheManager.ApexTransaction.contains('userId')) {
    // Use cached data
}

// Remove from cache
CacheManager.ApexTransaction.remove('userId');

// Get all keys
Set<String> keys = CacheManager.ApexTransaction.getKeys();

Example: Avoid Redundant SOQL

public User getUser(Id userId) {
    // Check cache first
    if (CacheManager.ApexTransaction.contains(userId)) {
        return (User) CacheManager.ApexTransaction.get(userId);
    }

    // Query if not cached
    User user = [SELECT Id, Name FROM User WHERE Id = :userId];

    // Cache for future use in this transaction
    CacheManager.ApexTransaction.put(userId, user);

    return user;
}

Example: Cache in Loops

for (Account acc : accounts) {
    // Cache account type metadata to avoid repeated queries
    String cacheKey = 'type' + acc.Type;

    if (!CacheManager.ApexTransaction.contains(cacheKey)) {
        AccountType__mdt metadata = [
            SELECT DefaultOwner__c
            FROM AccountType__mdt
            WHERE Type__c = :acc.Type
        ];
        CacheManager.ApexTransaction.put(cacheKey, metadata);
    }

    AccountType__mdt metadata = (AccountType__mdt)
        CacheManager.ApexTransaction.get(cacheKey);

    acc.OwnerId = metadata.DefaultOwner__c;
}

Limits

Transaction cache uses heap space. Be mindful of:

• Heap size limits (6MB synchronous, 12MB asynchronous)
• Large objects in cache consume significant heap
• Clear cache when no longer needed

Best Practices

1. Use for Short-Lived Data - Perfect for single-transaction caching
2. Clear When Done - Remove cached items you no longer need
3. Monitor Heap Usage - Large caches can exceed heap limits
4. Use Descriptive Keys - Make cache keys meaningful

See Examples →