feat: add lastRefreshTime to Load Request Success telemetry events

[RusovDmitriy]

No description provided.

[claude]

Claude finished @RusovDmitriy's task in 1m 0s —— View job

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Code Review

Review complete — verdict: LGTM with 2 minor observations. Click to expand.

• Read PR diff
• Review gateway.ts changes
• Review Rust changes (scan.rs, service.rs, shim.rs, node_export.rs)
• Check tests

Summary

Clean, well-scoped change. The Rust side threads lastRefreshTime from the load-result schema metadata through SpanId (min/oldest-wins semantics) and surfaces it on the Load Request Success telemetry emitted by both the postgres shim and native SQL handler. The JS gateway mirrors the same min-across-queries reduction. A unit test covers the SpanId min semantics including the "newer must not override older" case. Nice.

Observations (non-blocking)

1. packages/cubejs-api-gateway/src/gateway.ts:2095-2098 — NaN can slip past .filter(Boolean)

const lastRefreshTimestamps = results
  .map((r: any) => r.getRootResultObject()[0].lastRefreshTime)
  .filter(Boolean)
  .map((t: string) => new Date(t).getTime());

filter(Boolean) drops falsy strings, but new Date(t).getTime() runs after the filter — an unparseable-but-truthy string yields NaN, which poisons Math.min(...) and then throws RangeError: Invalid time value at new Date(NaN).toISOString(), killing the whole telemetry log line. In practice the value comes from Rust's to_rfc3339_opts, so this is unlikely to fire, but a defensive .filter(Number.isFinite) after the parse would make the log call bulletproof at zero cost.

2. rust/cubesql/cubesql/src/compile/engine/df/scan.rs:825 — only the first result contributes

load_data only takes result.into_iter().next() when recording the metadata, so if a load ever returns multiple results with distinct lastRefreshTime values, siblings are silently ignored. Matches the existing "first result wins" pattern in this function, so behavior is consistent — flagging only because the accompanying SpanId::set_last_refresh_time docstring implies aggregation across all contributors.

Strengths

• SpanId::set_last_refresh_time correctly implements min-semantics (older-wins) with a good docstring explaining why.
• Test at rust/cubesql/cubesql/src/transport/service.rs:1064 explicitly asserts that a later, newer value does not overwrite the recorded oldest — exactly the tricky case.
• Same field name and ISO-8601 format (SecondsFormat::Millis, UTC) used on both JS and Rust telemetry paths, keeping downstream consumers uniform.
• Change is additive; existing telemetry keys are untouched.

· branch: `feat-propagate-lastRefreshTime`

[codecov]

Codecov Report

❌ Patch coverage is 91.48936% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.46%. Comparing base (0bdbe18) to head (3b5d3a2).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
packages/cubejs-api-gateway/src/gateway.ts	50.00%	1 Missing and 1 partial ⚠️
rust/cubesql/cubesql/src/compile/engine/df/scan.rs	80.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #11283   +/-   ##
=======================================
  Coverage   79.45%   79.46%           
=======================================
  Files         473      473           
  Lines       97597    97642   +45     
  Branches     3539     3540    +1     
=======================================
+ Hits        77545    77590   +45     
+ Misses      19546    19545    -1     
- Partials      506      507    +1     

Flag	Coverage Δ
cube-backend	59.44% <50.00%> (-0.01%)	⬇️
cubesql	83.82% <95.34%> (+0.01%)	⬆️

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