Expose internal ReadySet metrics similar to SHOW GLOBAL STATUS

[vgrippa]

Is your feature request related to a problem? Please describe.
Currently, the only metric readily available is the cache hit count via SHOW CACHES. There is no visibility into runtime stats such as QPS, cache miss rates, unsupported query counts, or internal error rates. This lack of observability makes it difficult to understand ReadySet’s behavior under load, troubleshoot issues, or evaluate its performance impact.

Describe the solution you'd like
Introduce a SHOW STATUS-like interface (e.g., SHOW GLOBAL STATUS, SHOW SESSION STATUS) to expose internal operational metrics such as:
• Current QPS
• Cache hit/miss ratio
• Number of unsupported queries
• Eviction and invalidation stats
• In-flight query count
• Replication lag
• Query parse failures
• Cache warmup progress (if applicable)

These could be made available via a system table or status command

Additional context
This feature would significantly improve ReadySet’s observability, especially in production environments where monitoring behavior and debugging performance regressions are critical. Aligning with MySQL’s SHOW STATUS would also make adoption easier for existing users.

[altmannmarcelo]

@vgrippa we have #1355 which is currently not in our roadmap. I think they both serve the same purpose.

For now if you want to get in deep statistics you can:

curl  http://127.0.0.1:6034/metrics

most of descriptions are available at https://github.com/readysettech/readyset/blob/stable-250724/readyset-client-metrics/src/recorded.rs

We will look into re-prioritizing this.