Optimize get_claim_count() query for large stores

[mcliwanow]

Description

Optimizes get_claim_count() in ActionScheduler_DBStore for stores with large actionscheduler_actions tables.

The original query scans the (potentially huge) actions table:

SELECT COUNT(DISTINCT claim_id)
FROM wp_actionscheduler_actions
WHERE claim_id != 0 AND status IN ('pending', 'in-progress')

On a store with ~3M action rows, this took ~28 seconds to return 0.

The new query starts from the small actionscheduler_claims table and uses EXISTS to check the actions table:

SELECT COUNT(*)
FROM wp_actionscheduler_claims c
WHERE EXISTS (
   SELECT 1 FROM wp_actionscheduler_actions a
   WHERE a.claim_id = c.claim_id
   AND a.status IN ('pending', 'in-progress')
)

This returns in ~0.078 seconds (350x faster), because the claims table only holds active claims (typically a handful of rows), and EXISTS stops scanning at the first match.

If the claims-table query fails (e.g. the table doesn't exist yet during migration), the method falls back to the original query shape and logs the error.

Ported from WCCOM

Test instructions

Setup

Run the unit tests to verify correctness:

./vendor/bin/phpunit tests/phpunit/jobstore/ActionScheduler_DBStore_Test.php \ -c tests/phpunit.xml.dist --filter test_get_claim_count

All 7 new test cases should pass (runs as 42 with timezone rotation).

Manual verification

Prerequisites: A local WooCommerce site. Copy the updated ActionScheduler_DBStore.php into wp-content/plugins/woocommerce/packages/action-scheduler/classes/data-stores/.

1. Add this to wp-config.php to log queries:

define( 'SAVEQUERIES', true );

2. Then add this temporary mu-plugin to wp-content/mu-plugins/log-claim-count.php:

<?php
add_action( 'my_test_hook', function( $i ) {
    global $wpdb;

    $store = ActionScheduler::store();
    $count = $store->get_claim_count();

    $claim_query = null;
    foreach ( $wpdb->queries as $q ) {
        if ( str_contains( $q[0], 'actionscheduler_claims' ) && str_contains( $q[0], 'COUNT' ) ) {
            $claim_query = $q;
        }
    }

    error_log( sprintf(
        'During action %d: get_claim_count() = %d | query time: %fs',
        $i,
        $count,
        $claim_query[1] ?? 0
    ) );
} );

 add_action( 'action_scheduler_after_process_queue', function() {
    $store = ActionScheduler::store();
    error_log( sprintf( 'After processing: get_claim_count() = %d', $store->get_claim_count() ) );
} );

3. Test actions

• Schedule test actions via WP-CLI or a snippet:

 for ( $i = 0; $i < 5; $i++ ) { as_enqueue_async_action( 'my_test_hook', array( $i ) ); }

• Trigger processing — the log should show a non-zero count while actions run, then 0 after completion

- next processing should just show claims with 0

4. Cleanup

• Remove the mu-plugin
• Remove SAVEQUERIES from wp-config.php

[bor0]

Approving based on previous WCCOM review and neat results 🎉

[mcliwanow]

Hey @jorgeatorres 👋 Please let me know if you're the best person to review this PR. I'd appreciate someone else taking a look at it but I'm also happy to reassign review to someone else. Thanks!

[jorgeatorres]

@mcliwanow: thanks for the PR! This looks good to me and the improvements are quite nice. I left some feedback about the fallback query so we can discuss, but that's pretty much it. Thanks again!

[jorgeatorres]

LGTM. Ran a few tests with concurrent batches and also with actions marked completed without releasing the claim to confirm that the get_claim_count() matched the expected values. Thanks for the PR @mcliwanow! 🥇

---

Copy the updated ActionScheduler_DBStore.php into wp content/plugins/woocommerce/packages/action-scheduler/classes/data-stores/ [...]

💡 For future reference, you can always clone this repo and add it to your test site as a normal WP plugin. While enabled, it'll override the version of A-S bundled in WC, so no need to modify WC itself (and no need to even have WC installed).

[mcliwanow]

it'll override the version of A-S bundled in WC

Oh nice. That's good to know. Thanks!