WP Offload SES queue not processing when WP-CLI memory_limit is -1

Hi Delicious Brains support,

We’re using WP Offload SES Lite with AWS SES for WordPress transactional email. On one site, real emails were being added to the Offload SES queue but were not being sent when WP-Cron was run via WP-CLI.

The SES domain, DKIM, IAM credentials, and region all appear to be correct. The Offload SES test email sends successfully through AWS SES and has valid SES/DKIM headers. However, normal WordPress emails were sitting in the queue.

Site details:

• WordPress: 6.9.4
• PHP: 8.4.18
• WP Offload SES Lite: 1.8.0
• Server: Nginx / SpinupWP
• AWS SES region: eu-west-1
• WP-Cron disabled in WordPress and run via server cron using WP-CLI
• WP-CLI memory_limit: -1

The queue event existed and was running:

wp cron event list | grep -i ses

showed:

deliciousbrains_wp_offload_ses_queue_connection    now    1 minute

Manually running it completed successfully:

wp cron event run deliciousbrains_wp_offload_ses_queue_connection

Output:

Executed the cron event 'deliciousbrains_wp_offload_ses_queue_connection' in 0.01s.
Success: Executed a total of 1 cron event.

However, the queued emails remained queued.

The database showed that the emails and jobs existed and were available:

SELECT email_id, email_status, email_created, email_sent
FROM wp_oses_emails
ORDER BY email_id DESC
LIMIT 10;

Example output before the fix:

email_id    email_status    email_created          email_sent
81          queued          2026-04-28 09:30:39    NULL
80          queued          2026-04-28 09:30:35    NULL
79          queued          2026-04-28 09:26:08    NULL

And:

SELECT
    COUNT(*) AS total_jobs,
    SUM(reserved_at IS NULL) AS unreserved_jobs,
    SUM(available_at <= UTC_TIMESTAMP()) AS available_jobs
FROM wp_oses_jobs;

returned:

total_jobs    unreserved_jobs    available_jobs
3             3                  3

The worker lock was not set:

wp transient get deliciousbrains_wp_offload_ses_queue_connection --network

returned:

Warning: Transient with key "deliciousbrains_wp_offload_ses_queue_connection" is not set.

We then checked the WP-CLI memory state:

wp eval '
echo "memory_limit: " . ini_get("memory_limit") . "\n";
echo "memory_get_usage true: " . memory_get_usage(true) . "\n";
echo "80 percent threshold: " . (wp_convert_hr_to_bytes(ini_get("memory_limit")) * 0.8) . "\n";
'

Output:

memory_limit: -1
memory_get_usage true: 100466688
80 percent threshold: -0.8

We added a temporary filter to log the result of the WP Queue memory check:

add_filter('wp_queue_cron_memory_exceeded', function ($exceeded) {
    error_log('Offload SES queue memory_exceeded original value: ' . var_export($exceeded, true));
    error_log('Offload SES memory usage: ' . memory_get_usage(true));
    error_log('Offload SES memory limit: ' . ini_get('memory_limit'));

    return false;
}, 10, 1);

When the queue event was run again, the logs showed:

Offload SES queue memory_exceeded original value: true
Offload SES memory usage: 102563840
Offload SES memory limit: -1

Immediately after returning false from that filter, the queued emails were sent successfully:

email_id    email_status    email_created          email_sent
81          sent            2026-04-28 09:30:39    2026-04-28 10:03:04
80          sent            2026-04-28 09:30:35    2026-04-28 10:03:04
79          sent            2026-04-28 09:26:08    2026-04-28 10:03:04

It looks like the bundled WP Queue memory check may not handle PHP’s unlimited memory setting correctly. In vendor/WP-Queue/Cron.php, the memory check appears to multiply the result of get_memory_limit() by 0.8. When ini_get('memory_limit') is -1, this results in a negative threshold, so memory_get_usage(true) is always greater than the calculated limit and the queue worker exits before processing jobs.

The relevant behaviour appears to be:

memory_limit = -1
threshold = -0.8
memory_get_usage(true) >= -0.8
memory_exceeded = true

So the queue worker runs, but the processing loop never actually processes the available jobs.

As a temporary workaround we have added this mu-plugin:

<?php
/**
 * Plugin Name: Offload SES Queue Memory Fix
 *
 * WP Offload SES's bundled WP-Queue library appears to treat
 * WP-CLI's unlimited memory_limit (-1) as already exceeded.
 * This prevents queued SES emails from being processed by cron.
 */

add_filter('wp_queue_cron_memory_exceeded', function ($exceeded) {
    if (
        defined('WP_CLI')
        && WP_CLI
        && '-1' === ini_get('memory_limit')
    ) {
        return false;
    }

    return $exceeded;
}, 10, 1);

Could you confirm whether this is a known issue, and whether the queue memory check should treat memory_limit = -1 as unlimited rather than exceeded?

Thanks.