Oversized Folder Containing Menu Cache
Situation. A big size of the folder bitrix/managed_cache/MYSQL/menu: 1.9 Gb is revealed. The site has 4 types of cut-through menus and many pages. What is the problem and what can be done about it?
Cause. One cache file is created per page for each type of the menu used. In addition to that, if caching is set for various groups, multiply this number by the number of such groups. I.e., for each page you will have 4 files of the menu cache (if by groups, multiply by the number of groups). That explains the size of the folder.
Such a number of files by itself is not a problem, provided that there is enough space on the disk. The problem is that the accelerator (in our case, APC) saves these files into cache overfilling it.
Solution: Make sure that template.php and result_modifier.php contains no requests and heavy computing and exclude a file cache from the accelerator. Requests must be cached in menu_ext files.
apc.filters="-/bitrix/cache,-/bitrix/managed_cache/,-/upload/"
Note: If a certain menu type is not redefined in subfolders of the site, the following parameter may be specified upon connecting to the menu:
"CACHE_SELECTED_ITEMS" => "N",
As a result, the URL will not appear in the key during creation of the menu cache file. The selected level will be calculated after data from the cache are retrieved.