Access to historical index views is a hot spot during concurrent query. This can be observed in the following table. Except for the read(), everything in that table is being driven by SPORelation.getIndex() and LexiconRelation.getIndex().
The back traces are as follows:
This issue mainly effects the Journal. The IndexManger class on the cluster already has a cache for this.
Add a cache by (name,commitTime) to AbstractJournal to remove this hotspot.