Speed up warmup for loading the keys for value eviction bucket

Problem

Warmup with value eviction has two stages with value eviction

1. Load the keys
2. Load the documents, which might be via the access.log

As the number of keys increase the time taken to do the warmup will increase as all the keys need to be load for value eviction bucket.

Workaround

It's worth mentioning that full eviction bucket when warming up with an access.log will only load the keys that are required and documents when the access.log was generated.