Pattern 26 — Source Column Change Cascades to Stream Tables

Class: Rebuild (all affected stream tables) | Test: test_cookbook_26_source_column_cascade

When to use

An owned source table gains a new column that stream tables should use. aqueduct plan detects which stream tables reference the source and marks them for rebuild, generating a single coordinated plan.

Source migration file (updated)

-- migrations/sources/raw_c26.sql
-- @aqueduct:owned = true
CREATE TABLE public.raw_c26 (
    id     bigint,
    amount numeric,
    region text    -- new column
);

Updated stream table

-- migrations/streams/c26_agg.sql (updated to use new column)
-- @aqueduct:schedule = "30s"
SELECT id, region, SUM(amount) AS total
FROM public.raw_c26
GROUP BY id, region;

Plan output

  ALTER TABLE public.raw_c26 ADD COLUMN region text;    [base-table DDL]
  ! c26_agg    [rebuild]   base-table DDL change cascade

Notes

• Stream tables that do not reference the changed column are unaffected.
• The base-table ALTER and stream-table cascade are always in a single coordinated plan — aqueduct will never emit one without the other.
• Tier 2 changes (new tables, non-referenced columns, indexes) are delegated to Atlas/sqitch via a pre-hook.