Problem/Motivation
In #3437499: Use placeholdering for more blocks and on Slack we (@berdir, @catch and myself) did some digging and came to the conclusion that the single cache lookups of placeholders no longer makes sense in Renderer. We now have a ::getMultiple() method on the render cache and we know we're going to look all of the placeholders up in one go in CachedStrategy.
So why don't we skip the retrieving of placeholders in Renderer altogether and allow CachedStrategy to do that? The ones we didn't find will still end up getting rendered live, but at least this way we went to the cache once instead of for every placeholder individually.
Steps to reproduce
N/A, check metrics after the change
Proposed resolution
Skip single placeholder cache GETs and offload to getMultiple()
Remaining tasks
Investigate and discuss potential fall-out from moving this bit around
User interface changes
N/A
Introduced terminology
For discussion in this issue:
- PRC
- PlaceholderingRenderCache
- VC
- VariationCache
API changes
N/A
Data model changes
N/A
Release notes snippet
N/A