Inspect a plan and lineage graph

This how-to shows how to inspect a Prism-backed lazy plan without executing it.

Use inspect_plan(...) when you need the full inspection record. Use inspect_lineage(...) when you only need the lineage graph.

Build a lazy plan

from pub::incql import LazyFrame
from pub::incql.functions import col, eq, str_lit, sum
from models import Order

def paid_spend_summary(orders: LazyFrame[Order]) -> LazyFrame[Order]:
    return (
        orders
            .filter(eq(col("status"), str_lit("paid")))
            .group_by([col("customer_id")])
            .agg([sum(col("amount"))])
    )

Inspect the plan

from pub::incql import inspect_plan

summary = paid_spend_summary(orders)
inspection = inspect_plan(summary)

println(inspection.plan_id)
println(inspection.output_fields[0].name)

inspect_plan(...) does not execute the plan. It reads the local Prism state behind the lazy carrier and returns plan targets, output fields, Prism nodes, lineage, artifacts, diagnostics, and unsupported-evidence markers.

Read lineage directly

from pub::incql import inspect_lineage

lineage = inspect_lineage(summary)

for edge in lineage.edges:
    println(edge.relationship.value())

Lineage is plan-local evidence. It explains how the authored plan relates fields and relations before backend binding or execution. For exact record fields and current limits, see Local inspection (Reference).