Comprehensive Guide to Magento 2 Index Management

Update On Save vs. Update By Schedule

Update On Save mode

In the indexing mode, Update On Save has the sense to initiate the reindex for a definite instance after it’s been changed. In our case (with product labels) we depend on products. This means that while one concrete Magento 2 product is changed we need to reindex our instance for this product programmatically. To programmatically reindex the instance in Magento 2, you need to do the following:

• Create an app/code/Amasty/Example/etc/adminhtml/events.xml file:

<?xml version="1.0"?>

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation=
"urn:magento:framework:Event/etc/events.xsd">
<event name="catalog_product_save_after">
<observer name="reindex_event" instance=
"Amasty\Example\Model\Observer\Backend\CatalogProductSaveAfterObserver" />
</event>
</config>

• Create an app/code/Amasty/Example/Model/Observer/Backend/CatalogProductSaveAfterObserver.php file:

<?php

namespace Amasty\Example\Model\Observer\Backend;

use Magento\Framework\Event\Observer;
use Magento\Framework\Indexer\IndexerRegistry;
use Magento\Framework\Event\ObserverInterface;

class CatalogProductSaveAfterObserver implements ObserverInterface
{
/**
* @var IndexerRegistry
*/
private $indexerRegistry;

public function __construct(IndexerRegistry $indexerRegistry)
{
$this->indexerRegistry = $indexerRegistry;
}

public function execute(Observer $observer)
{
$product = $observer->getEvent()->getProduct();

if ($product) {
$this->indexerRegistry->get('amasty_example')->reindexRow($product->getId());
}
}
}

By doing so, we have added an observer for a product save action.
After a product is changed, the indexer will be called and the ID of the updated product will be transferred.

Update By Schedule mode

If you change the Update On Save mode for the Update By Schedule one, the app/code/Amasty/Example/etc/mview.xml config file will be read and MySQL triggers will be created. This means that while deleting, adding, updating rows in the defined subscriptions tables, the entity_id column will be added and amasty_example_cl will be written into the table (it’s created automatically for the work in the Update By Schedule mode):

Also, there is a version_id (AUTO_INCREMENT) field in the amasty_example_cl table. The field is compared to the version_id field from mview_state for a current indexer.
As a result, in our execute($ids) processor will get only those instances that have been changed after the previous ?rone launch (amasty_example_cl.version_id > mview_state.version_id).

How to set up cron job in Magento 2 for working with indexers?

The main Cron jobs for working with indexers are defined in the vendor/magento/module-indexer/etc/crontab.xml file.

When launching Cron job by indexer_reindex_all_invalid (every minute), executeFull will be started for invalid indexers (they are marked in the Indexers grid with REINDEX REQUIRED status). It is intended for a full reindex, that is, in this case for all the invalid indexers, the table with the saved information will be rewritten.

When starting Cron job by indexer_update_all_views (every minute) all the indexers that work in the Update On Schedule mode will be launched.

While launching it by indexer_clean_all_changelogs (every hour) the _cl tables (in our example it’s amasty_example_cl) indexers will be purged of entries with version_id below the latest version in the mview_state table.

Note: Check out how to reindex Magento 2 indexers manually without cron.

All the presented Cron jobs belong to the index group. The work of the Cron job group can be set up here Stores -> Advanced -> System:

How to manage Magento 2 custom indexers through the command line?

To see a complete list indexer commands in Magento 2, click the link.

Note: While executing the bin/magento indexer:reindex amasty_example command, you may face the error:
‘Amasty Example index is locked by another reindex process. Skipping.’

You can solve it in two ways:

1. Either you have to wait for the end of the reindex process, which is now being executed,
2. or the reindex process has been interrupted for any reason and the status meaning hasn’t been changed in the table, as the process wasn’t finished:

If this occurs, you can reset indexer in your Magento 2 via the bin/magento indexer:reset amasty_example command. It will change the working status to invalid and while launching the next reindex it will work.

Wrap-up

That’s all for today.

If you have questions or suggestions, feel free to pose them in the comments below.

And stay tuned for new technical posts!