Stash, thanks to its hierarchical cache, needs to do several lookups to resolve a cache item, and is incapable of doing several cache item lookups at once.

Symfony Cache uses a tagging model instead as of Symfony 3.2 and supports multi get, and will hence:

• Give us better performance, specifically when using memcached/redis on other machines (latency)
  • Extreme example is reduction of cache lookups from 42 to 10 (and later 1 with multi get lookups in SPI) when doing a content search with 10 hits
• Can allow us to much better handle cache purging on complex operations like tree operations
  • Should be able to get rid of all occurrences of purging all cache when specific items can't be found, aka "Timber!" in the code base

Target for story

• Change form Stash to Symfony Cache in SPI Persistence cache
• Get rid of Timber! occurrences by means of cache tagging instead (try to stay in sync with tagging done on http cache for similar concepts)