Documentation describing how to update PHP memory limit is required

Thanks for doing this page. I know one of the first things that will come up is "You said to put ... in my ... file, but WHERE?" Many of us know, or can figure out, where things should go, but many drupallers are afraid of messing with these files, so giving them an exact spot makes them feel better about doing it.

In the introductory part, we should also include: "PHP 4 had a default of 8MB; PHP 5 has a default of 16MB, but your host may have changed this."

settings.php

If you scroll down, you will see a section labeled "PHP settings." Beneath this you will see several "ini_set" lines (directives). At the end of that list, add a new line that says:

ini_set('memory_limit',             '16M');

Note that some sites may require a higher value.

php.ini

On many Windows systems, this file will be in the WINDOWS directory, so you may not be able to access it.

If you do have access, scroll down to see if there is a section labeled "Resource Limits." If so, there may already be a directive for the limit that you can edit. If not, add a line at the end of this section that says:

memory_limit = 16M      ; Maximum amount of memory a script may consume (16MB)

If there is no section already for this, place the above line at the end of the file.

.htaccess

There may already be sections (especially if you are using the file that came with Drupal) that say something like:

# PHP 5, Apache 1 and 2.
<IfModule mod_php5.c>
  php_value magic_quotes_gpc                0
  php_value register_globals                0
  php_value session.auto_start              0
  php_value mbstring.http_input             pass
  php_value mbstring.http_output            pass
  php_value mbstring.encoding_translation   0
</IfModule>

Locate the correct section for your version of PHP and Apache. (If you're not using Apache, consult with the appropriate manuals on how to do this.)

Preceding the closing "," add a line that reads:

  php_value memory_limit 16M

I will be happy to make these changes to the page if there is agreement.

"PHP 4 had a default of 8MB; PHP 5 has a default of 16MB, but your host may have changed this."

I'm not sure it helps to add this. The default settings depends on how your PHP is packaged. On MAMP for example, PHP5 has 8MB by default, on debian I think it's 128MB. It varies, and there is no such general rule.

On many Windows systems, this file will be in the WINDOWS directory, so you may not be able to access it.

can you elaborate on this? In which circumstances aren't able to access php.ini on Windows?

re .htaccess, I think we could gain in simplicity by adding the line at the beginning of the Override PHP settings section, just before the 3 IfModule blocks. Otherwise, it becomes quite complex for the newbie to find which version PHP and Apache they are using. At least this way you are sure that the setting you add is applied, and if for some reason it doesn't work, you'll know it right away on your site.

PHP default: That is true. These figures are from the PHP manual. If this is superfluous, we can delete it.

Windows: I doubt seriously if a shared Windows host is going to let any user update the Windows directory... If it's their own PC, they can probably do anything they want.

.htaccess: If they put it at the top and there is another directive later on that lowers it, haven't they wasted their time?

.htaccess: well, in the default .htaccess shipped with Drupal there isn't such memory_limit rule, so it's ok. If there is already such rule in the file, it means they modified the file earlier, so we can almost assume they know what they are doing.

Looks pretty good. I suspect a few very tentative folks are still going to post "exactly where..."

thanks nancyw and vjordan for your constructive feedback. I merged them and updated the page: http://drupal.org/node/207036
I kept the option to change host at the end. More feedback/edit welcome.

Looks much better.

I just had a thought though. It says, "Some sites may need more than 16MB..." and the "php.ini" section states, "this change will affect all ... on the server." So perhaps, at the end of that section, and above ".htaccess" there should be a line that says something like, "The next two solutions are site-specific and, in some cases, may be more appropriate choices."

This is for those who have several sites, most of which run just fine in 16M, but one is glutted by many modules or even one module that needs a lot of memory (I have a module like that).

thanks nancyw, updated.

Yes, I can modify it.

".htaccess" - affects only the sites within this [multi-site] installation.

"settings.php" - affects only the site using this file.

I added this:

(See the <a href="http://drupal.org/node/207036">Increase PHP memory limit</a> page in the <em>Troubleshooting FAQ</em> for additional information on modifying the PHP memory limit.)

to the requirements page.

Thanks