[Forum] Cache Issues [Resolved by web host]

[Amaury]

At first it seemed like login issues, but then I realized that it was cache issues. I updated passwords almost everywhere I visit yesterday, so like anytime you change your password on a vBulletin forum, once the Session Timeout passes, regardless if Remember Me? is checked, you get logged out. In my case, when 10:48 AM PST passed, I was logged out because I was not active since 10:23 AM PST, and we have our Session Timeout set to 25 minutes.

Anyway, sometime after 10:23 AM PST yesterday and before I got back from my GED study around 2:10 PM PST, our forum has been getting stuck on old data for a certain amount time, and we are having to hard-refresh pages for it to get accurate. For example, if I'm viewing the index at 9:15 PM and reload it at 9:20 PM, it'll still say 9:15 PM unless I do a hard-refresh. If it's more than 10 minutes, we don't have any problems. It's only when it's less than 10 minutes.

When I thought it was login problems, like I said in my first paragraph, even though I had just cleared Mozilla Firefox's data the night before before going to bed, I tried clearing it again to no avail. I then tried Google Chrome, and it still didn't work. Additionally, if I reloaded the index (at first I also thought it was just the index page), I would appear logged in, but if I reloaded it again, I appeared logged out. I reloaded it several times with the same results. While that was happening, there was also a bunch of characters added to the URL after "forum.php."

Finally, the URL returned to normal and I was always appearing logged in, but I kept getting old versions from about 10 minutes ago, maybe? I can tell when it gets stuck on old data, too, because it loads extremely quickly -- so fast that I can barely see the loading circle on the tab.

This is still going on.

So, would this be a forum issue or a server issue?

Thanks!

[beishe8]

So, would this be a forum issue or a server issue?

Seems to be a server issue.(Provided your ISP is not using a proxy)

[Amaury]

Something I forgot to add is that our server is run by Bluehost.

[George L]

Yes seems alot of folks recently reported cache issues and i think all of them are with bluehost, so they probably they changed something at their end ? You on shared or dedicated server ?

CTRL+F5 hard refresh in browser window might help ?

[Amaury]

Yes seems alot of folks recently reported cache issues and i think all of them are with bluehost, so they probably they changed something at their end ? You on shared or dedicated server ?

Dedicated.

[George L]

Definitely get bluehost to investigate http://www.bluehostforum.com/showthr...irects-caching

[George L]

Looks like bluehost is a cloudflare hosting partner http://www.cloudflare.com/hosting-partners - so bluehost may have enabled cloudflare railgun https://www.cloudflare.com/railgun or other tech on servers ??

[Kajouka]

I use hostmonster (same company) and we are all having this problem! I received this response from them.

Hello,

Have you tried setting turning off the content cache in vbulletin itself?
AdminCP > Settings > Options > Server Settings and Optimization Options > Disable Content Caching > Yes

In addition, you should be able to disble caching through your headers. For example:

Header set Expires "Thu, 19 Nov 1981 08:52:00 GM"
Header set Cache-Control "no-store, no-cache, must-revalidate, post-check=0, pre-check=0"
Header set Pragma "no-cache"

Unfortunately the apache module mod_cache cannot be disabled on our servers, due to our server configuration not allowing CacheDisable in the .htaccess files.

Please let us know if you have further questions or concerns.

Thank you,
Derek
Level II Site/Script Compatibility

The first was an option I don't have on my version and the second (which I tried php, meta tags everything) did not work. If you get info, please share!

[Kirk Fitzgerald]

Same problem, but with FASTDOMAIN and they're blaming vBulletin settings on my part and refusing to look any further into it, so annoying as it's obviously something wrong on their end and unless they accept responsibility my site's doomed!

[Kajouka]

izz found this!!!

I may have found a fix. Look for "Add No-Cache HTTP Headers" in your admin cp settings. Set it to yes. Still testing, but this seems to be working.

This is working for me now! try it please!

- - - Updated - - -

It's in the cookies btw

[Kirk Fitzgerald]

izz found this!!!


This is working for me now! try it please!

- - - Updated - - -

It's in the cookies btw

This temporarily patches the problem, but we cannot leave our forums running like that, re-building every page as members navigate the site is going to start creating problems all of its own in no time at all. It's making navigating the site cumbersome and laggy, my host has opted to totally ignore me now, very troubling!

[George L]

I use hostmonster (same company) and we are all having this problem! I received this response from them.

The first was an option I don't have on my version and the second (which I tried php, meta tags everything) did not work. If you get info, please share!

if hostmonster and bluehost use same mod_cache (and enabled it) then there is root of your problem http://httpd.apache.org/docs/2.2/mod/mod_cache.html

Hello,

Have you tried setting turning off the content cache in vbulletin itself?
AdminCP > Settings > Options > Server Settings and Optimization Options > Disable Content Caching > Yes

In addition, you should be able to disble caching through your headers. For example:

Header set Expires "Thu, 19 Nov 1981 08:52:00 GM"
Header set Cache-Control "no-store, no-cache, must-revalidate, post-check=0, pre-check=0"
Header set Pragma "no-cache"

Unfortunately the apache module mod_cache cannot be disabled on our servers, due to our server configuration not allowing CacheDisable in the .htaccess files.

Please let us know if you have further questions or concerns.

Thank you,
Derek
Level II Site/Script Compatibility

As the web host doesn't allow disabling mod_cache, you'd be left with 3 options

1. set no-cache and wear higher cpu loads and lower performance OR
2. set admincp option mentioned above with same performance penalty OR
3. move web hosts as most web hosts don't enable mod_cache (disabled by default in apache)

[Amaury]

if hostmonster and bluehost use same mod_cache (and enabled it) then there is root of your problem http://httpd.apache.org/docs/2.2/mod/mod_cache.html



As the web host doesn't allow disabling mod_cache, you'd be left with 3 options

1. set no-cache and wear higher cpu loads and lower performance OR
2. set admincp option mentioned above with same performance penalty OR
3. move web hosts as most web hosts don't enable mod_cache (disabled by default in apache)

What kind of performance issues would disabling content caching cause?

[George L]

What kind of performance issues would disabling content caching cause?

1. browser caching performance outlined at http://gtmetrix.com/leverage-browser-caching.html. no-cache does opposite all that

What is browser caching?

Every time a browser loads a webpage it has to download all the web files to properly display the page. This includes all the HTML, CSS, javascript and images.

Some pages pages might only consist of a few files and be small in size - maybe a couple of kilobytes. For others however there may be a lot of files, and these may add up to be several megabytes large. Twitter.com for example is 2mb+.

The issue is two fold.

These large files take longer to load and can be especially painful if you're on a slow internet connection (or a mobile device).
Each file makes a separate request to the server. The more requests your server gets simultaneously the more work it needs to do, only further reducing your page speed.
Browser caching can help by storing some of these files locally in the user's browser. Their first visit to your site will take the same time to load, however when that user revisits your website, refreshes the page, or even moves to a different page of your site, they already have some of the files they need locally.

This means the amount of data the user's browser has to download is less, and fewer requests need to be made to your server. The result? Decreased page load times.

How does it work?

Browser caching works by marking certain pages, or parts of pages, as being needed to be updated at different intervals. Your logo on your website, for instance, is unlikely to change from day to day. By caching this logo image, we can tell the user's browser to only download this image once a week. Every visit that user makes within a week would not require another download of the logo image.

By the webserver telling the browser to store these files and not download them when you come back saves your users time and your web server bandwidth.

Why is it important?

The main reason why browser caching is important is because it reduces the load on your web server, which ultimately reducing the load time for your users.

2. admincp

Add No-Cache HTTP Headers
If you enable this option, no-cache HTTP headers will be added to each page. These cause full page data to be re-requested from the server every time the user gets a page, which will increase bandwidth; it may additionally cause an increase in server load as it will cause more pages to be served.

[Amaury]

1. browser caching performance outlined at http://gtmetrix.com/leverage-browser-caching.html. no-cache does opposite all that



2. admincp

Ah, thank you. Two questions, though:

1. So, in short, loading time may be a bit longer depending on the user's Internet connection. Am I understanding that correctly?
2. In their example, they say some things like logo images don't need constant updating because it's unlikely to change on a daily basis. However, things like the index, forums, threads, user profiles and everything else that's similar do need constant updating, so what exactly is the issue going on now? I'm still not completely understanding it. They did a security update, but how is that causing the issues?