[TYPO3-core] RFC #11410: Speed up BEgetRootLine by reusing parts of the rootline from the cache

[Rupert Germann]

Steffen Kamper wrote:
> have a look at
> #11271: Use 2 level cache for BEgetRootLine
> where i used a 2-level-cache for the rootline and had awesome
> performance boost with huge site. As i did cache on the complete result,
> we may find a combined solution to get the maximum speed out of it.

according to the benchmark results, combining is the way to go. In theory it
would be possible to add the 3rd (caching framework based) level from
#11271 additionally to the 2 caches from my follow up suggestion, but that
would also require to do quite a lot of additional effort to make sure that
the persistent cache does not deliver false results. eg. adding a tcemain
hook to clear this cache when it's needed. Deciding whether the cache
should be cleared or not will eat up additional performance.  

Without further testing I'd say that the benefit of a persistent (3rd) cache
layer will not justify the needed efforts.

but if you have test results that say something else.... feel free to
convince me ;-)

greets
rupert