detect-n-plus-one

name	detect-n-plus-one
description	Detect N+1 query patterns in a trace, where one parent operation triggers many near-identical child spans (often database calls). Use when a trace is slow and shows repeated downstream calls, or when the user asks about N+1, repeated queries, or chatty DB access.
license	Apache-2.0
metadata	{"author":"jaegertracing","version":"1.0"}
allowed-tools	search_traces get_trace_topology get_span_details

Detect N+1 Query Patterns

When this applies

A parent span has many child spans with the same operation name and similar duration, typically database queries or RPC calls.

Procedure

1. Find candidate traces with search_traces.
2. Pull the span tree with get_trace_topology; group child spans by operation name under each parent.
3. Flag any group with more than 10 near-identical siblings as a potential N+1 pattern. Check that children have similar durations (within 2x of the median).
4. Inspect repeated siblings with get_span_details to confirm they target the same downstream service and carry similar attributes.
5. Report: the parent span (service, operation), the repeated child operation, the count, total wall-clock time consumed, and whether children run sequentially or in parallel.

Gotchas

• Parallel fan-out can look like N+1 but is intentional — check whether children overlap in time before flagging.
• Batch operations may share an operation name but carry different payloads — check span attributes to distinguish.