[IGNITE-12550] Add page read latency histogram per data region

• Type: Improvement
• Status: In Progress
• Priority: Major
• Resolution: Unresolved
• Component/s: persistence
• Ignite Flags: Docs Required, Release Notes Required
• Assignee: Alexey Goncharuk
• Reporter: Alexey Goncharuk
• Created: 16/Jan/20 12:36
• Updated: 29/Dec/20 08:57

Description

During an incident I experienced a large checkpoint mark duration. It was impossible to determine whether this was caused by a stalled disk because of large number of long page reads or by some other reasons.
Having a metric showing the page read latency histogram would help in such cases.
We already have a pagesRead metric, just need to measure the read timings.