[wp-trac] [WordPress Trac] #57271: Cron unschedule / reschedule event errors

[WordPress Trac]

#57271: Cron unschedule / reschedule event errors
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 Reporter:  domainsupport               |       Owner:  audrasjb
     Type:  defect (bug)                |      Status:  assigned
 Priority:  normal                      |   Milestone:  Awaiting Review
Component:  Cron API                    |     Version:  6.0
 Severity:  normal                      |  Resolution:
 Keywords:  has-patch needs-unit-tests  |     Focuses:
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Comment (by galbaras):

 `update_option()` calls `wpdb::update()`, which doesn't check for errors,
 but it called `wpdb::query()`, which seems to be outputting messages when
 errors occur. However, it doesn't do this when the database connection is
 lost, in which case, I retries, and the dies if unsuccessful.

 This may be our real culprit. See
 [https://core.trac.wordpress.org/browser/tags/6.1/src/wp-includes/class-
 wpdb.php#L2098 here].

 Also, `wpdb::check_connection()` uses `$this->reconnect_retries`, which is
 set to 5 without a filter, and `sleep(1)`, also without a filter in the
 sleep duration. So if the connection isn't restored in 5 seconds, it's
 game over, wheras in real life, restoring the connection can take a lot
 longer.

 Changing these values arbitrarily could cause pages to stall for too long,
 but assuming this is a rare occurrence, or, as is the case with cron,
 waiting isn't an issue, this may not be such a bad idea.

 In fact, checking again in 1 second, then 5 seconds, then 10 seconds, then
 30 seconds, then 1 minute can help get a quick reconnection when possible,
 but still a reconnection when that takes longer. It's the sort of retry
 logic used in networking and other systems to increase reliability.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/57271#comment:24>
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