The PHP setting max_input_vars determines how many input variables may be accepted [limit is applied to $_GET, $_POST and $_COOKIE superglobal separately]. If there are more input variables than specified by this directive, an E_WARNING is issued, and further input variables are truncated from the request.
There are a lot of big or potentially big forms in Moodle, such as:
- Site administration tree search
- Editing roles
- Grading courses with big number of participants
- Large quizzes and quiz settings
The default value for max_input_vars in PHP is 1000, this is not enough for many cases.
If you are using PHP 7 the recommended value for the max_input_vars in Moodle is 5000 but you can still use Moodle with the lower value. Moodle code has a workaround that allows to submit the forms even with bigger limit however this workaround is not perfect. It is much better to increase the setting.
e.g. in Ubuntu 20.x, within /etc/php/7.4/apache2/php.ini, find this section and remove the comment [semi-colon] and edit the line to increase the size:
; How many GET/POST/COOKIE input variables may be accepted
;max_input_vars = 1000
max_input_vars = 5000
If you are using PHP 8 the minimum value of 5000 is required. By default PHP 8 sets to display startup errors [see [1]]. This means that the warning about exceeding max_input_vars appears before the workaround even applied.
To change max_input_vars you can either set it in php.ini or modify it in runtime, for example for Apache you can create .htaccess file:
php_value max_input_vars 5000
Installing and upgrading help
Installation Error on php max_input_vars
- ◄ Error driver database problem detected
- Moodle Messages problem after upgrading to 3.9 ►
Hi, I have installed moode to Ubuntu server 16. while trying to install moodle it shows to set the php input vars to 5000. I have already set it to 10000. After changing the values I have restarted the Apache2 server. the error keeps on showing. then I have checked the php-info.. It shows the max_input_vars is 10000.
Apart from this what should I do. I have also tried .htaccess file creation.
max_input_vars is
a DB config/tweak [for mysql/mariadb my.cnf file]. Restart your DB service - catch 22 = shared hosting? 'SoS', Ken
Hello Ken, I have restarted
mysql service. I have hosted this in aws. I have even tried restarting the instance too. nothing worked. Dang! My 'bad' ... true it is a php setting - having 'senior moments' today! Is DB service localhost [on same machine as code] or is it remote [another server]? Check config.php for DB server. Not long ago I was helping someone hosting with AWS and the DB
server could be accessed only by Amazon's internal fully qualified domain name. 'SoS', Ken I do think that it is odd that noorul says php.info shows 10000. So, I don't know? Ken, max_input_vars is a php.ini setting, as far as I know. noorul, perhaps you didn't make this change in the correct php.ini file. If you had the ability to go into your Moodle,
admin/Server/php info, you would see the information from your php.ini file. If max_input_vars is not what you set it to, then you either edited the wrong file or have a typo in your php.ini file. Another technique, without Moodle working, is to create a simple info.php file and put it on your server. It will show the same information that
Moodle shows you. I'll attach this file.
Make sure the environment.xml file in code/admin/ is of the moodle version you are trying to install.
In a search of all moodle3x/admin/environment.xml directories/files for 'max_input_vars' [acquired via git] shows that only 3.5 had an optional in check for max_input_vars
fgrep 'max_input_vars' ./moodle3?/admin/environment.xml
./moodle35/admin/environment.xml:
Search of versions
3.10 and 3.11 code/admin/environment.xml didn't show any check on max_input_vars:
Kens-MBP-2:MDLGITTEST kentask$ fgrep 'max_input_vars' ./moodle310/admin/environment.xml
Kens-MBP-2:MDLGITTEST kentask$ fgrep 'max_input_vars' ./moodle311/admin/environment.xml
'SoS', Ken
Hi ken, It shows max input vars = optional What version of Moodle are you trying to install? Since server is Linux [Ubuntu] you should have php-cli installed and can access to it via ssh. One can install a moodle via command line: first check you do have php-cli installed: php -v should show that. Then cd /path/to/moodlecode/admin/cli/ php install.php You will be prompted for all the same things the GUI would have prompted for. 'SoS', Ken Hi Ken, I’m trying to install Moodle 3.11 and I have php -cli installed. And I can see php - cli is installed. I can access the install.php file. Is there any changes I should make ?
and I don’t use guy version. pls help me with this. I am trying to help ... but .. help is only as good as answers to questions ... and those answers include what was shown to you! What did you see when you issued: php -v Ubuntu doesn't have a '16' ... there is a 1.6 ... when it comes to installing moodle, details [versions] are important. Please see: //www.syndrega.ch/blog/#php-and-dbms-compatibility-of-major-moodle-releases to make sure you have minimal versions required for 3.11 installed. Ok 3.11 is the version you are attempting to install ... please verify that by looking at the version.php file in code root. Show me what it shows you!
Have never seen that max_input_vars check ... but then again, I install via command line. Maybe, just maybe, one can 'get by' this issue by installing via command line. Before you try, however, do an environment check from command line: cd /path/to/moodlecode/admin/cli/ php checks.php If ALL is ok,
that script will show: OK: All 'status' checks OK Let's see if command line install by passes your issue. 'SoS', Ken Hi Ken, As you said, I tried php checks.php. it shows the below errors.
Ken: You might need to do a git pull because that line is in
3.10.4 and 3.11.
Duh! Begin ... red in face ... Yep ... you are correct ... ./moodle310/version.php:$release = '3.10.3 [Build: 20210325]';// Human-friendly version name prior to git pull git pull on 310: on 311 which [red in face] was a dev release [double red in face]: check for the check fgrep 'max_input_vars' ./moodle310/admin/environment.xml fgrep 'max_input_vars' ./moodle311/admin/environment.xml one more reason to use git! Thanks, Leon. Let's hope OP having issue might consider git install. 'SoS', Ken
Related follow up and a high recommendation to use git for installs and updates/upgrades ... Moodle
code now has a checks.php that does an environment check from CLI. That's great ... now my up and upgrade scripts will run checks.php and pause. If I [red in face] wasn't aware of a new check 'making it's way into required, doing the check before the pull means I haven't touched the code files nor have I altered the DB and tables! Can cancel my
up/upgrade ... fix ... then run again - which is a time saver!!! [don't have to restore site from backup]. Softac and other one click wonders at present don't run checks. One more reason to stay away from them! Anyhoo ... an additional 5 cents! 'SoS', Ken
./moodle311/version.php:$release = '3.11dev [Build: 20201224]';// Human-friendly version
name
not there
fgrep 'max_input_vars' ./moodle31?/admin/environment.xml renders nada.
admin/environment.xml | 4 +-
admin/environment.xml | 187 +
present and optional
present and
optional
Noorul: Your screenshot of the PHP setting:
max_input_vars => 10000 => 10000
Is from the command line [php
-i] but the error is from the web interface [GUI]. So maybe you need to restart the web server service to read the new max_input_vars setting from the PHP .ini file. The service you need to restart might be apache2 or php-fpm.
If you're still getting this error then you can see max_input_vars for the web server by creating a file called phpinfo.php in the Moodle source code folder containing two lines: