AgentSkillsCN

starrocks-docs

查阅StarRocks查询概要指标与调优文档。在需要理解某项指标的含义，或了解如何优化查询性能时使用此功能。

SKILL.md
--- frontmatter
name: starrocks-docs
description: Look up StarRocks query profile metrics and tuning documentation. Use when you need to understand what a metric means or how to optimize query performance.
allowed-tools: WebFetch, WebSearch, Read

StarRocks Documentation Lookup

Look up information about $ARGUMENTS from StarRocks official documentation.

Primary Documentation Sources

  1. •

    Query Profile Operator Metrics (most relevant for metric definitions): https://docs.starrocks.io/docs/best_practices/query_tuning/query_profile_operator_metrics

  2. •

    Query Profile Tuning Recipes (bottleneck patterns and fixes): https://docs.starrocks.io/docs/best_practices/query_tuning/query_profile_tuning_recipes/

  3. •

    Query Planning (optimizer behavior, join strategies, distribution): https://docs.starrocks.io/docs/best_practices/query_tuning/query_planning/

Tasks

1. Search Documentation

  • •For metric definitions: fetch the Query Profile Operator Metrics page first
  • •For bottleneck patterns: fetch the Query Profile Tuning Recipes page
  • •For optimizer/planning questions: fetch the Query Planning page
  • •Use WebSearch for broader StarRocks documentation if needed

2. Explain the Metric/Concept

Provide:

  • •Definition: What the metric measures
  • •Units: Time (ns/us/ms/s), bytes, rows, count
  • •Location: CommonMetrics vs UniqueMetrics, which operator types have it
  • •Interpretation: What high/low values indicate

3. Performance Context

If relevant, explain:

  • •Bottleneck patterns: What issues this metric can reveal
  • •Related metrics: Other metrics to check alongside
  • •Optimization tips: How to improve if values are problematic

4. NorthStar Integration

Check if this metric is already displayed in NorthStar:

  • •Search js/scanRender.js for scan-related metrics
  • •Search js/joinRender.js for join-related metrics
  • •If not displayed, suggest whether it should be added

Common Metric Categories

Scan Operator Metrics

  • •Time: ScanTime, IOTaskExecTime, IOTaskWaitTime, SegmentInit, SegmentRead
  • •Rows: RawRowsRead, RowsRead, PullRowNum, filter metrics (ZoneMapIndexFilterRows, etc.)
  • •I/O: BytesRead, CompressedBytesRead, IOTime

Join Operator Metrics

  • •Build: BuildHashTableTime, HashTableMemoryUsage, RowsSpilled
  • •Probe: SearchHashTableTime, ProbeConjunctEvaluateTime

Common Bottleneck Patterns

  • •Cold storage: High IOTaskExecTime + BytesRead
  • •Thread starvation: High IOTaskWaitTime + low PeakIOTasks
  • •Data skew: Large gap between __MAX_OF_* and __MIN_OF_*
  • •Fragmentation: High RowsetsReadCount/SegmentsReadCount + long SegmentInit
  • •Missing filter pushdown: PushdownPredicates near 0, high PredFilterRows