Cron Stuck: Drupal 6
(Moving to a new topic, because I noticed that I was writing in a topic that had Drupal 5.x taxonomy. My issue is on a Drupal 6.9 server.)
Cron is getting stuck.
The current behavior is that I fight with it, deleting variables and the cache and every once in a while I can get cron to run manually. Once. Then it’s stuck again and I get the dreaded: “Attempting to re-run cron while it is already running” warning.
Here's the history:
-------------------------------
- For weeks I’ve been running cron.php manually using http://www.weavezinedev.com /cron.php and it’s been flawless
- About 5 days ago, it got stuck (I wasn’t checking reports then, so didn’t realize.)
- Went on Drupal.org to research and learned about going in Devel/variable and deleting cron_semaphor and cron_last. Sometimes this unsticks Cron.php, sometimes it doesn’t.
- Disabled suspect modules: Update Status, Backup And Migrate (didn’t help)
- Set Search indexing to 10 items per Cron
- Deleted Cache (for a while tried running without caching, but that didn’t seem to help) Sometimes clearing the cache unsticks cron, sometimes it doesn’t.
I checked the changelog I’ve been keeping for site development, and the things that happened around the time cron stopped working were:
- Added advertisements (about 20-30) using the Advertisement module
- Added a bunch of content manually (about 40 body texts)
- Imported about 40 WordPress blog posts and their comments using the “WordPress Import” module (Note: this generated errors when it ran, but the content showed up.)
Working against me is that some articles on the site are quite long. (11+ pages printed out) and the fact that my host (SiteGround) won’t let me up the php max_execution_time in php.ini
Thoughts? Advice?
Also, probably not related but FYI, I set up a crontab using cPanel, and get the following error when it runs. I’ve contacted the SiteGround’s tech support about this and they’re working with me to fix it.
-------------------------------------------------------------------------
Looking up www.weavezinedev.com
Making HTTP connection to www.weavezinedev.com Sending HTTP request.
HTTP request sent; waiting for response.
Alert!: Unexpected network read error; connection aborted.
Can't Access `http://www.weavezinedev.com/cron.php'
Alert!: Unable to access document.
lynx: Can't access startfile
-------------------------------------------------------------------------
Two final questions:
- Cron.php is supposed to finish executing within 30 seconds, right? I’m not hurting anything if after 2-3 minutes I’ve going in and deleting the cron_semaphore and cron_last variable, am I?
- I've seen mention in some forum topics about a Cron log? I'm not finding anything like that in my Drupal admin or in the files in my Drupal install directory. Does it exist? If so, can someone give me a pointer? I'd love to have more information about where exactly Cron.php (aka bootstrap.inc) is failing.
_
I had a similar problem on my 5.x installation; I finally debugged it by saving a copy of includes/module.inc and then changing module_invoke_all to read :-
<?php
function module_invoke_all() {
$args = func_get_args();
$hook = array_shift($args);
$return = array();
foreach (module_implements($hook) as $module) {
if ($hook == 'cron') {
$now = microtime(true);
watchdog('module_invoke_all',"calling $module");
}
$function = $module .'_'. $hook;
$result = call_user_func_array($function, $args);
if ($hook == 'cron') {
$now = microtime(true) - $now;
$now = number_format($now, 5);
watchdog('module_invoke_all',"return from $module after $now sec.");
}
if (isset($result) && is_array($result)) {
$return = array_merge($return, $result);
}
else if (isset($result)) {
$return[] = $result;
}
}
return $return;
}
?>
This left entries in the log showing calls to, and the return from, the various modules with a cron hook.
Pete.
Fixed: ad_cache_memcache was the culprit. Cron Log is Awesome!
Pete,
Thanks for the logging snippet! I got the same bit of code from a Drupal buddy and it made all the difference. I hope something like this makes it into Drupal 7. Cron is such a black box without some sort of log to show you where it's breaking.
So, with cron logging installed, it took about two minutes to clear out the cron_semaphore one last time, re-run cron and identify the problem module. On my server, ad_cache_memcache, was not returning during cron runs and leaving the cron_semaphore set. I can disable it and cron runs just fine, both manually and from an automated crontab. I can enable it and watch cron break again, with all the symptoms above. It's great to be able to toggle the repro!
Thanks for taking the time to stop and help a newbie out!
The past two days of debugging and research have really taught me a lot about cron. Whew!
Syne Mitchell
Editor of WeaveZine
www.weavezine.com
_
Glad I could help!
I had the same problem myself, and the code change was the only way to debug the issue.
I agree that it would be enormously useful to be able to toggle logging of cron invocations - perhaps you should suggest it?
Pete.
Guys I'm having the same
Guys I'm having the same problems... I added the code as specified and am now looking for the output in the logs... but which logs can I find this in? Watchdog reports the same old problem and doesn't give any more info.
Thanks,
Adam
_
Watchdog as in 'recent log entries', right?
Should be right there; see http://mongolia.charityrallies.org/sites/all/files/Screenshot-9.png
Pete.
How to resolve problem module
I also found this very helpful as it allowed me to identify the problem module. However I am at a loss to know what to do next - the problem module is simplenews - which is called but doesn't return.
I am on drupal 5, have been using simplenews for several months, this is the first time simplenews itself has caused the cron to hang.
My situation right now is that half the mail from a simplenews bulletin has gone out and the rest is stuck.
Any suggestions?
_
Best to post this question in the simplenews list of issues.
Having said that, the last stable release of the 5.x version is eight months behind the 6.x release candidate; we abandoned it a while ago due to the lack of control over the mailouts, which were at best ugly HTML, and used phplist and the Drupal phplist module instead.
It's not an ideal solution, but we're relatively happy with it; there's a very apparent dropoff in support of 5.x modules...
Pete.
I used this code on drupal
I used this code on drupal 6
and waiting for anything to appear on the log entries
cron is now stuck
i think i will take time to get unstuck
then i need to re run it and watch the log entries
http://www.WOGOOH.com
http://www.i-bloggers.com
The code pbarnett posted is
The code pbarnett posted is for D5. I tried it on D6 but got errors all over the place. Does anyone have a similar code that is D6 compatible? I'm also trying to solve this problem, and finding the source would be a good start.
_
I modified module.inc (after saving a copy of the original) on a D6 test site, adding the same code as I used for D5.
It works fine for me... the modified function is -
<?php
function module_invoke_all() {
$args = func_get_args();
$hook = $args[0];
unset($args[0]);
$return = array();
foreach (module_implements($hook) as $module) {
$function = $module .'_'. $hook;
if ($hook == 'cron') {
$now = microtime(true);
watchdog('module_invoke_all',"calling $module");
}
$result = call_user_func_array($function, $args);
if ($hook == 'cron') {
$now = microtime(true) - $now;
$now = number_format($now, 5);
watchdog('module_invoke_all',"return from $module after $now sec.");
}
if (isset($result) && is_array($result)) {
$return = array_merge_recursive($return, $result);
}
else if (isset($result)) {
$return[] = $result;
}
}
return $return;
}
?>
Pete.
Thanks Pete, I really
Thanks Pete, I really appreciate this. Big help with this elusive problem.
Pete, thanks so much for this!
So good of you to post this for those of us who're running 6.x and have been running afoul of this problem. (Mine seems to have been caused by a recent install of Lucene: now at least I should be able to work out which node is making the trouble.)
Thanks again! D.
Diane Duane | The Owl Springs Partnership | Co. Wicklow, Ireland
http://www.dianeduane.com | http://www.youngwizards.com | http://www.europeancuisines.com
_
Hey, no problem...
It's helped me troubleshoot more dodgy code (mostly mine) than a little!
Pete.
Received Fatal error using D6 snipit above
Thanks for the code snippet. I think it will help me debug what is happening with my cron error. I got the following error while running cron using the code snippit ubove for D6:
Fatal error: Cannot redeclare module_invoke_all() (previously declared in /home/fillmor1/public_html/newsite/includes/module.inc:13) in /home/fillmor1/public_html/newsite/includes/module.inc on line 503Here is something strange. I backed out the code changes to module.inc and I still get the error. Is there some cache to clear?
Thanks for any help on this,
Scott
Drupal 6.14
Cron maintenance tasks Last run 8 hours 38 min ago
You can run cron manually.
MySQL database 5.0.77mm0.1
PHP 5.2.9
PHP memory limit 96M
PHP register globals Disabled
Unicode library PHP Mbstring Extension
Update notifications Enabled
Upload progress Not enabled
Web server Apache/1.3.41 (Unix) mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 FrontPage/5.0.2.2635.SR1.2 mod_ssl/2.8.31 OpenSSL/0.9.8b mod_status/0.2mm
cURL Library 7.15.5
jQuery UI 1.6
module.inc fatal error problem solved
It was a caching problem in firefox. Worked fine in IE so I cleared firefox browser cache and it fixed the problem.
Sorry for the confusion,
Scott
_
No problem; your post will help anyone with the same issue!
Pete.