Index Modes — Update on Save vs Update by Schedule

How Real-Time Works

Product Save -> Index Updated Immediately -> Response

When a product is saved, the index is updated synchronously before the response is returned.

When to Use Real-Time

• Small catalogs (< 10,000 products)
• Low-frequency updates
• When immediate consistency is required
• Development environments

Configuration

php bin/magento indexer:set-mode realtime catalog_product_price

Real-Time Flow

// In product model save()
public function afterSave()
{
    parent::afterSave();
    // Index updated immediately
    $this-> indexer->reindex($this->getId());
}

Performance Impact

-- Real-time adds ~50-200ms to each save
-- For bulk operations:
-- 100 products: +5-20 seconds
-- 1000 products: +50-200 seconds

Pros and Cons

How Scheduled Works

Product Save -> Index Flagged as Invalid -> Response
Cron Run -> Invalid Indexes Reindexed

The index is not updated immediately. Instead, the indexer state is set to 'invalid' and a cron job processes it later.

When to Use Scheduled

• Large catalogs (> 10,000 products)
• High-frequency updates
• Bulk import operations
• Production environments

Configuration

php bin/magento indexer:set-mode schedule catalog_product_price

Scheduled Flow

// In product model save()
public function afterSave()
{
    parent::afterSave();
    // Just mark as invalid
    $this->indexerState->setStatus(
        Indexer::STATE_INVALID
    );
}

// Cron job processes invalid indexes
public function execute()
{
    $invalidIndexers = $this->getInvalidIndexers();
    foreach ($invalidIndexers as $indexer) {
        $indexer->reindexFull();
    }
}

Changelog Table

Scheduled indexing uses a changelog table:

-- Tracks changes for incremental reindex
CREATE TABLE catalog_product_price_cl (
    entity_id INT,
    updated_at TIMESTAMP
);

Pros and Cons

Decision Matrix

Per-Indexer Configuration

Different indexers can use different modes:

# Price: schedule (heavy computation)
php bin/magento indexer:set-mode schedule catalog_product_price

# Category product: schedule
php bin/magento indexer:set-mode schedule catalog_category_product

# Search: real-time (immediate consistency)
php bin/magento indexer:set-mode realtime catalogsearch_fulltext

Hybrid Approach

# Most indexers on schedule
php bin/magento indexer:set-mode schedule catalog_product_price
php bin/magento indexer:set-mode schedule catalog_category_product

# Search on real-time
php bin/magento indexer:set-mode realtime catalogsearch_fulltext

Mode Comparison

Switching from Real-Time to Schedule

# 1. Set mode
php bin/magento indexer:set-mode schedule catalog_product_price

# 2. Full reindex to initialize changelog
php bin/magento indexer:reindex catalog_product_price

# 3. Verify
php bin/magento indexer:status catalog_product_price

Switching from Schedule to Real-Time

# 1. Full reindex first
php bin/magento indexer:reindex

# 2. Set mode
php bin/magento indexer:set-mode realtime catalog_product_price

# 3. Verify
php bin/magento indexer:status catalog_product_price

Checking Current Mode

# Show all modes
php bin/magento indexer:show-mode

# Output:
+------------------------------------+------------+
| Indexer                            | Mode       |
+------------------------------------+------------+
| catalog_product_price              | schedule   |
| catalog_category_product           | schedule   |
| catalogsearch_fulltext             | realtime   |
+------------------------------------+------------+

Impact of Mode on Bulk Operations

// Import with real-time (slow)
foreach ($products as $product) {
    $product->save(); // Index updated each save
}
// 1000 products * 200ms = 200 seconds

// Import with schedule (fast)
foreach ($products as $product) {
    $product->save(); // Just flag as invalid
}
$this->indexer->reindexList($productIds); // Batch reindex
// Total: ~10 seconds