MetricsQL

VictoriaMetrics PromQL superset. Syntactically backwards-compatible; semantically different for a subset of queries. Lead with the diffs — that's where users get burned. PromQL fundamentals live in the sibling promql skill; this covers only what PromQL doesn't.

References

• Behavioral diffs from PromQL — [${CLAUDE_SKILL_DIR}/references/behavioral-diffs.md] rate/increase/delta/changes diffs, _prometheus-suffixed variants, scalar/instant-vector unification, NaN handling, name retention, implicit conversions, auto-aligned subqueries, default_rollup lookback, staleness markers.
• MetricsQL-only extensions — [${CLAUDE_SKILL_DIR}/references/extensions.md] Rollup family, WITH templates, multiple-or filters, default/if/ifnot ops, group_left(*) prefix, keep_metric_names, [Ni] step, numeric suffixes, aggregate limit N, boundsLabel, fractional durations, Graphite, multi-line.
• Full function catalog — [${CLAUDE_SKILL_DIR}/references/functions-catalog.md] All rollup, transform, label-manipulation, aggregate functions by category, with PromQL/MetricsQL provenance.
• Query API enhancements — [${CLAUDE_SKILL_DIR}/references/api-enhancements.md] extra_label, extra_filters[], round_digits, limit, timestamp formats, stats response, cluster vmselect URL layout, multi-tenancy.