Since 2023-03-14, performance of VE's getPageHTML function has become much slower on hewiki, with the median latency degrading from about 130ms to 600ms. See https://grafana.wikimedia.org/goto/F4rvB3fVz?orgId=1

Hypothesis: this is caused by a degraded parser cache hit rate. However, the hit rate seems fine globally, see https://grafana.wikimedia.org/goto/gq2_B3fVz?orgId=1. We do not have per-wiki stats for the parser cache hit rate, so we can't check whether it is degraded for hewiki for some reasons.

Context:
Hebrew Wikipedia (hewiki) is one of the wikis where we are testing out Visual Editor in "direct mode". This means Visual Editor is accessing Parsoid directly as a PHP library, and makes use of MediaWIki's parser cache, rather than relying on RESTbase.