Menu router refactoring

History

In Drupal 6 there were big changes with the menu_router system. As far as I can tell, it was a performance based decision. It was a time of low performance (compare to SSD) SATA drives. So storing router items in the database was a good idea, due to better performance. But it was not fast enough. menu_local_tasks started to be stored in cache_menu (per tab_root) Actions were added in Drupal 7 and were stored in cache_menu as well. Backdrop added context_links but this data was not cached. As a result, there was around +10% response time added to each page.

Ideas in patch

My first assumption based on SSD popularity. There is no significant performance difference between a reading file and selecting a record from the database.

Menu_router is hierarchy based data. Instead of selecting the database to match path variable, I decided to read JSON file by path.

Tabs, actions and context items can be prepared on menu_rebuild phase. I added tabs.json, action.json and context.json files. It's kinda a cache that updates on menu_rebuild call.

Result

• no significant changes on tests performance.
• some performance boost when context links are in use. But not big one.
• no need to cache local_tasks anymore, as a result, there is less pressure on cache_menu table and fewer queries per page request.
• step forward to remove MENU_MAX_PARTS (9) limitation.

Backward compatibility

I did not remove _menu_router_save() function. menu_rebuild call it to update menu_router table. Any contrib module that requires records from menu_router table is not going to be broken.

Need help & review

I am not good with documentation and function name. Please help me to properly update documentation and rename functions.