Calendar not loading: 500 Internal Server Error

[Ronya Banks]

Hi, Stephen,

The full calendar is stuck on loading. When I check the console, I see that I’m getting a 500 internal server error for this:
http://www.ashevillemeditation.com/wp-admin/admin-ajax.php?action=eventorganiser-fullcal&start=2015-08-30&end=2015-10-04&timeformat=g:i+a&users_events=false

The calendar page is at ashevillemeditation.com/calendar.

Thanks in advance for your help!

Suzanne
(web developer for Ronya Banks)

[Stephen Harris]

Hi Ronya,

What do the error logs say caused the 500 error? Where those logs live will depend on your server’s configuration, but you might find the log file in the root of your www directory.

[Ronya Banks]

Okay, just took a look. I don’t know how to make heads nor tails of these logs, but I hope you do.

This is from the log:

[Wed Sep 30 02:00:26 2015] [error] [client 166.137.248.86] Premature end of script headers: admin-ajax.php, referer: http://www.ashevillemeditation.com/calendar
[Wed Sep 30 02:00:27 2015] [error] [client 166.137.248.86] File does not exist: /home/ronyabanks/ashevillemeditation.com/internal_error.html, referer: http://www.ashevillemeditation.com/calendar

[Stephen Harris]

hmm… that ajax response took a very long time to decide it was going to fail. I wonder if that’s causing the server to terminate the request without responding to the client?

Were there any changes made prior to this happening? New plug-in added, theme activated, content added or settings changed?

I’ve tried hitting a few pages, and this is what I found the load time (time to first byte) to be:

• http://www.ashevillemeditation.com/wp-admin/admin-ajax.php: 4-7 seconds
• http://www.ashevillemeditation.com 0.2 seconds
• http://www.ashevillemeditation.com/wp-admin: 4-7 seconds

For the first one I would expect to see an empty page with just ‘0’ almost immediately, but its taking anywhere between 4 and 7 seconds. One the other hand the home page is very respectable. I would suspect that you have a caching plug-in installed, but that pages that are not cached (typically urls under wp-admin/) are painfully slow.

If there were no changes that were made prior to this issue occurring I would recommend that you deactivate other plug-ins until performance improves, as I think this might be the culprit. Otherwise, revert those changes that were made.

[Ronya Banks]

Hi, Stephen,

I put a copy of the website on a web host for sites under development and then tried deactivating all plugins other than Event Organiser. This did not make any difference in the calendar’s ability to load. Then I tried reverting to various of the pre-installed WP themes, but the calendar still doesn’t load.

I’m no longer getting any related messages in my error log, but on the Firefox Dev Console, the network request for /wp-admin/admin-ajax.php?action=eventorganiser-fullcal&start=2015-09-27&end=2015-11-01&timeformat=g%3Ai+a shows this response:

Maximum execution time of 30 seconds exceeded in /wp-content/plugins/event-organiser/includes/event-organiser-utility-functions.php on line 143

This seems to be in reference to the function eo_get_blog_timezone().

Here is the calendar page on the dev site: http://aim2015.openairwebdesign.com/calendar

Any ideas?

Thanks, Suzanne (developer for Ronya Banks)

[Stephen Harris]

Hi Suzanne,

I took a copy of the site’s events using the iCal feed (I got 49 events, is that about right?). Some were weekly lasting over 10 years, but nothing that caused too much concern in the way of volume. On my local test site (running on a VM on my laptop) I averaged between 8-9 seconds for the calendar to load – way below the 30 second limit imposed by your host.

Do you know what the server’s CPU / memory is, as this will probably be a large contributor to the time taken to process the request.

I also tested 3.0.0-beta with the above events, and found that the calendar load time improved to 5-7 seconds; if you wanted to experiment with that on the test site to see if it improves matters I’d be happy to give you a copy.

[Ronya Banks]

Hi, Stephen,

Thank you so much for the time you’ve spent looking at this issue. You really offer outstanding plugin support!

I’m not sure what the server’s CPU/memory is. It’s a DreamHost Shared Hosting account. I tried some googling to find out the server’s resources but couldn’t find an answer. At any rate, I assume DreamHost offers server resources similar to what is offered on most other web hosts’ shared server accounts.

I would love to try the the beta version. Thanks so much for the offer!

One thing I’m confused about, though, is that I’m not able to get the calendar’s events to load at all, and yet they loaded for you in 8-9 seconds. Do you know why this would be?

Also, for events that will be recurring indefinitely, I often just set the schedule to end 10 or more years in advance. Would it be helpful not to create such a long range?

Thanks again for your help,

Suzanne

[Stephen Harris]

One thing I’m confused about, though, is that I’m not able to get the calendar’s events to load at all, and yet they loaded for you in 8-9 seconds. Do you know why this would be?

Assuming all other plug-ins had been disabled, and the theme in use was a core theme – the only thing can be the server’s processing power. Simply put the server is running out of time to produce the json response for rendering the calendar. Plug-ins and some themes will add work for the server to do, thus effectively slowing it down and is often a big reason for memory exhaustion or timeouts. But I am a little stumped that’s running out of time rather than memory. I can’t comment on the quality of Dreamhost’s hosting arrangements, but I can’t imagine they would be degrees worse that an VM on my laptop.

Also, for events that will be recurring indefinitely, I often just set the schedule to end 10 or more years in advance. Would it be helpful not to create such a long range?

Yes, although as of 3.0.0 the advantage of doing so will be diminished. I’ll be in touch with beta shortly.

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