Module channel_derivation 

Channel type derivation from query plan analysis.

This module analyzes query plans to automatically determine whether sources need SPSC (single consumer) or broadcast (multiple consumer) channels.

Key Principle

Users never specify broadcast mode. The planner analyzes MVs and sources to derive the correct channel type automatically:

• If a source is consumed by exactly 1 MV → SPSC (optimal)
• If a source is consumed by 2+ MVs → Broadcast

Example

CREATE SOURCE trades (...);

CREATE MATERIALIZED VIEW vwap AS
  SELECT symbol, SUM(price * volume) / SUM(volume) AS vwap
  FROM trades
  GROUP BY symbol, TUMBLE(ts, INTERVAL '1' MINUTE);

CREATE MATERIALIZED VIEW max_price AS
  SELECT symbol, MAX(price)
  FROM trades
  GROUP BY symbol, TUMBLE(ts, INTERVAL '1' MINUTE);

In this example, trades source has 2 consumers (vwap and max_price), so the planner derives Broadcast { consumer_count: 2 } for trades.

Structs

ChannelDerivationResult

Channel derivation result with additional metadata.

MvDefinition

Materialized view definition for channel derivation.

SourceDefinition

Source definition for channel derivation.

Enums

DerivedChannelType

Channel type derived from query analysis.

Functions

analyze_mv_sources

Analyzes a single MV to extract its source references.

derive_channel_types

Analyzes query plan to determine channel types per source.

derive_channel_types_detailed

Derives channel types with additional analysis metadata.