Question2Answer Q&A - Recent questions tagged caching

There is an issue in Q2A image upload when cache feature is enabled

Thu, 10 Mar 2022 05:31:42 +0000

I have set max upload size is 8MB in ckeditor image upload feature. I have also enabled filesystem cache for 1 hour.

When I upload an image greater than 8MB while asking question then I get Javascript error that "maximum upload size is 8MB". All right till now!

The issue is that this error is also getting cached and it affects all the user on the q2a site. If users uploads an image lesser than 8MB size Even then they have the same Javascript error as "maximum upload size is 8MB" and the image is not getting uploaded.

Please help me how can I resolve this.

Thank you

I am trying to create html cache using opcache. Anyone intrested ?

Sun, 04 Jul 2021 04:29:18 +0000

I am trying to create html cache using opcache. Anyone intrested ?

Why Q2A is not using redis it is better than memcached?

Fri, 30 Apr 2021 02:31:51 +0000

Why Q2A is not using redis it is better than memcached?

i have a proplem in cache

Thu, 07 Jan 2021 12:24:26 +0000

my website that use q2a have alot of php request so after a few hours my server have been cached, i make a test in many servers proplem stay

Do I need to disable caching on the site, if using Cloudflare cache?

Wed, 15 Jul 2020 11:16:24 +0000

How do I enabled Caching?

Mon, 18 May 2020 20:41:51 +0000

I would like to know how to enable Caching on my site Sturtz QnA

What's the purpose of "delete expired cache" button?

Mon, 06 May 2019 21:14:30 +0000

Expired cache appears to be replaced automatically by new cache. So what's the purpose of the button "delete expired cache"?

Leverage browser caching for the following cacheable resources

Thu, 24 Jan 2019 20:36:15 +0000

https://www.example.com/qa-content/jquery-3.3.1.min.js (expiration not specified)
https://www.example.com/qa-theme/SnowFlat/images/icons/close-black.png (expiration not specified)
https://www.example.com/qa-theme/SnowFlat/images/icons/search-mobile.png (expiration not specified)
https://www.example.com/qa-theme/SnowFlat/images/vote-buttons-2.png (expiration not specified)
https://www.googletagmanager.com/gtag/js?id=UA-92155952-2 (15 minutes)
https://www.googletagservices.com/activeview/js/current/osd.js?cb=%2Fr20100101 (50 minutes)
https://www.googletagservices.com/activeview/js/current/osd_listener.js?cache=r20110914 (50 minutes)
https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js (1 hour)
https://www.google-analytics.com/analytics.js (2 hours)

To what extent the caching is effective?

Mon, 11 Sep 2017 18:11:41 +0000

QA 1.8 comes with caching feature which can be also easly implemented to QA 1.7.5.

I just wonder if any of you have tested efficiency of this caching method. To what extent it helps to increase the performance of a frequently changing (active) q2a website? Can any one give metric regarding this, whoever tested it? What are the pros and cons of enabling caching?

This is my current gtmetrix without caching: (on a shared host)

Query string performance tuning suggestion from a tool

Thu, 28 Apr 2016 11:02:30 +0000

Remove query strings from static resources

Most proxies, most notably Squid up through version 3.0, do not cache resources with a "?" in their URL even if a Cache-control: public header is present in the response. To enable proxy caching for these resources, remove query strings from references to static resources, and instead encode the parameters into the file names themselves.

/?qa=image&qa_blobid=14251717397400842271&qa_size=30
/qa-plugin/q2a-social-share-master/css/social-share.css?1.6.1
/qa-plugin/q2a-social-share-master/fonts/social-icon.ttf?-p1x0ul
/qa-theme/SnowFlat/fonts/fontello.woff?70015067
/qa-theme/SnowFlat/fonts/ubuntu.css?1.7.4
/qa-theme/SnowFlat/images/spinner-icon-14x14.gif?1410117644
/qa-theme/SnowFlat/qa-styles.css?1.7.4

I ran an online performance test against my website and was give the above suggestion to improve performance. Does this make sense and Is there anything we can do ?

Let's all brainstorm to solve this caching issue once for all

Sun, 28 Feb 2016 00:43:50 +0000

Lets all brainstorm to get this thing done.

Few considerations:

1- Ideally we need to cache every single page( question pages, front page, list views, user pages, ) except admin-only pages

2- Each time an event fires, cache copy of pages affected by this event have to be updated.

3- Plug-ins also have to get notified of this cache page updates.

Two very typical scenario:

Scenario 1. A user answers a question.

- As a result his/her score has to be updated in his/her user page, the activity page, the question page, the questions list page, walls of other users if he/she has posted anything.

Scenario 2. Each time a page gets visited, its cached version has to be updated too. why? because page views are displayed in question pages at the top.

In one word, each time there is an update/write to db, the corresponding cached pages have to be updated too (except the admin ones) .

Very expensive to implement right?

Suggesting approach:

so we need to lower our expectation and only concentrate on updating caching for more important stuff and leave some of the components to be later read and updated via ajax calls (e.g. users scores, page views, votes etc)

convention:

- Lets call important stuff like questions, answers, comments and the scaffoldingof the page (related CSS and HTML DOM) class 1 component

- Lets call user scores, vote values, flag values etc, class 2 components

Example: For a question page, the question itself, the answers, the comments to be cached and leave the rest to be updated by ajax calls only after entire page is fully loaded ( from cache copy).

1- Each time a question or answer or a comment is posted/updated (class 1 components changed), update the cache of corresponding pages.

Updating or creating a cache for a page means: rendering entire page (class 1 and class 2) and storing them all together as cached copy

2- Each time a page is requested:

if (the cache copy of that page is available)

{ -load cache copy (the class 1 components which are up to date and correct + cached copy of class 2 which might not be up to date )

- update class 2 components like users scores, votes, flags by ajax calls

e.g. the users sees the entire page loaded quickly and notices that the user A had score 85, but after 1-2 second his/her score get updated to value 93.

}

else {

- load class 1 components of the page from db

- update class 2 components by ajax calls to db

- update the cache copy of that page

}

I "think" this approach can also take care of complications the third party plugins add too

Question: is this possible?

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Please kindly avoid posting comments like, it is not that easy, it needs time etc. Instead try to contribute please

Security errors for users.

Sat, 15 Aug 2015 10:57:28 +0000

Hi, I have been getting a lot of security errors for users login/register recently. I guess it has something to do with cookies. Can some one help? I have a doubt this is due to the caching plugin.

"PHP Question2Answer form security violation for login by anonymous (time 760s in future) on /login?to"

I can see that the client time is in future- but I surely don't want to deny such users access.

How do I clear cache?

Sat, 27 Jun 2015 18:01:05 +0000

How do I clear cache? Items that I removed still keep showing up on my website q2a website? I have made many changes via admin panel, but I am still unable to see them and would like to see the changes immediately. I have already cleared the cache and cookies out of all my browser, and that method doesn't work. Someone please help me. What files do I need to alter in order to get immediate changes? What code must be changed?

Why not question2answer have caching system or caching plugin?

Wed, 24 Jun 2015 07:12:04 +0000

Blobs do NOT get cached? How to turn on blob cache?

Mon, 25 Nov 2013 04:48:54 +0000

I remember that gidgreen once said all blobs get cached by the browser, correct headers are sent. Looking to the Firefox Developer console, I see that this is not the case instead code "304" (yellow bubble) they get loaded completely anew, code "200".

So, how to turn on the blob cache?

Note: All my blobs are loaded from the database.

And I am using htacess to define the cache time:

    ExpiresByType image/gif        "access plus 1 month"
   ExpiresByType image/jpg        "access plus 1 month"
   ExpiresByType image/jpeg        "access plus 1 month"
   ExpiresByType image/png        "access plus 1 month"

PS: You can see the same effect here in this forum.

I'm building a Cache plugin/layer - What would you like to see it do?

Sun, 09 Oct 2011 20:30:37 +0000

I'm building a cache plug-in layer for q2a. The basic idea is that, for most pages, the entire page can be cached, while other pages can only cache certain sections.

For pages like home that build elements from different places, I'm going to cache each major section as a cache file. When that part of the page is being built, I'll check if there's a cache file for it and use that. If there isn't I'll execute the code and store the result in a cache file to use next time.

For pages like a question, the entire page can be cached until there's a change event. To do this, I'm going to deliver the cached version of the entire page in the init of the modual if it's not a POST. If there's no cache file, I'm going to let the page execute and capture the output for the cache by turning on the output buffer with ob_start. If there's an event (like an upvote or comment) I'll delete the cache file so a new cache file could be created.

I'm going to store all cache information under the question ID so that I can wipe out the entire cache for that question, insuring the most up-to-date result each time.

Is this something you'd like to us? Please add your feedback and suggestions on this idea.

Edit: The existing version is very buggy. Use it for informational purposes only, not in a production environment. I'm working on an update that'll address a lot of the issues with this beta version.

Is caching possible in Q2A?

Tue, 12 Oct 2010 08:44:57 +0000

I've noticed that Q2A sends several headers to prevent caching on all pages:

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

However, for old questions the chance of them changing is quite low. So wouldn't it be beneficial to remove those headers if a question is more than a week old, or set them to cache for at least a few hours?

Also, would it be at all feasible to cache pages server-side, or parts of pages? If a user is logged in there will be certain parts that can't be cached, but a good chunk of the HTML should be cacheable, right?