A rate() series over a metric whose occurrences are confined to a short
burst within a much wider queried range (e.g. sum by (code)
(rate(KeyPressed[5m])) against a ~10h log where all key presses happen
in the first 10s) rendered as broken: the line simply stopped at the
last real occurrence, and the chart's x-axis auto-scaled to the tiny
span of actual data points rather than the queried range, silently
narrowing a 10-hour view down to ~10 seconds with no indication anything
was off.
Backend (src/engine.rs): windowed_rate_series now appends a synthetic
boundary point at start_ms/end_ms (computed via the existing
rate::rate_at against the original occurrence points, so a boundary
inside a still-warm window gets its true partial value rather than a
hardcoded 0) whenever the real series doesn't already reach that edge.
Wired into both the bare rate() and sum()/avg(rate()) evaluate_promql
branches, which already had start_ms/end_ms in scope.
Frontend (PanelChart.tsx/Dashboards.tsx): the line chart's XAxis now
uses an explicit numeric domain pinned to the panel's queried range
(passed down from Dashboards.tsx's PanelPreview) instead of recharts'
default auto-scale-to-data-extent, so sparse data can no longer make
the axis look narrower than what was actually queried.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o
