INTROBLOCK · 01
ETL · 7 MIN PREVIEW
ETL/ELT, CDC & real-time integration
Move data without losing it. CDC, idempotency, schema evolution — the three things that keep pipelines on-call quiet.
CONCEPTBLOCK · 02
ETL is a load-balanced contract problem
Every pipeline is a contract between a producer (the source DB or app) and a consumer (the warehouse, lake, or downstream service). The contract has three clauses: ordering, delivery, and shape. CDC (Change Data Capture) tightens the ordering clause — every change is captured in commit order. Idempotent sinks tighten delivery — replays are safe. Schema evolution tightens shape — fields can be added or widened without breaking consumers. Get all three right and your pipeline becomes boring. Boring is the goal.
TIPETL vs ELT is mostly about *where* you transform. Both can be batch or streaming. Don't conflate the axes.
WATCH OUTMost outages are at-least-once delivery hitting a non-idempotent sink. Solve idempotency before you solve scale.
DIAGRAMBLOCK · 03
Source -> CDC -> queue -> sink
Debezium tails the WAL — no triggers, no polling, no lock contention.
CODEBLOCK · 04
Debezium connector — 12 lines that capture every row change
YAML1name: pg-source
2config:
3 connector.class: io.debezium.connector.postgresql.PostgresConnector
4 database.hostname: pg
5 database.port: 5432
6 database.user: cdc
7 database.password: cdc
8 database.dbname: app
9 topic.prefix: app
10 plugin.name: pgoutput
11 publication.autocreate.mode: filtered
12 table.include.list: public.orders,public.users
pgoutput uses Postgres logical replication (built in since PG10). publication.autocreate keeps DDL out of your way.
CHEATSHEETBLOCK · 05
Five things to remember
01ELT > ETL when your warehouse can transform faster than your pipeline can.
02CDC needs primary keys. Tables without PKs need surrogate ones added first.
03Idempotent sink = (key, version) upsert. No exceptions.
04Schema evolution: additive changes only. Drops require a deprecation window.
05Backpressure on the sink, never on the source. The DB is not your buffer.
MINIGAME · RAPIDFIRETFBLOCK · 06
True or false: 6 seconds each
CDC via WAL/binlog has lower production-DB impact than polling.
CLAIM 1/5 · READY · scroll into view
LESSON COMPLETEBLOCK · 07
Pipeline contract: locked.
NEXTHello Debezium: WAL to Kafka in 50 lines
WHAT YOU'LL WALK AWAY WITH
Real skills, real career delta.
Skills you'll gain
07- Run Debezium without panickingWorking
Outcome from completing the course: run debezium without panicking.
- Build idempotent sinksWorking
Outcome from completing the course: build idempotent sinks.
- Evolve schemas without 4 a.m. pagesWorking
Outcome from completing the course: evolve schemas without 4 a.m. pages.
- ETL vs ELT in 2026Working
Covered in lesson sequence — drop-in ready.
- Debezium CDC patternsWorking
Covered in lesson sequence — drop-in ready.
- Schema evolutionWorking
Covered in lesson sequence — drop-in ready.
- Real-time integration with Kafka ConnectWorking
Covered in lesson sequence — drop-in ready.
Career & income delta
Career moves
- Lead a ETL/ELT, CDC & real-time integration initiative on your team — most orgs have it on the roadmap and few have shipped it.
- Consulting work at $150-300/hr — 'ETL shipped to production' is a sought-after specialty in 2026.
- Move from generic IC to platform/AI-platform team where ETL/ELT, CDC & real-time integration expertise is the entry ticket.
Income impact
- $15-40K bump for senior ICs adding ETL/ELT, CDC & real-time integration to their resume.
- Freelance / consulting demand for the same skill: $150-300/hr in 2026.
- Closing enterprise deals often hinges on demonstrating the production patterns from this course.
Market resilience
- ETL/ELT, CDC & real-time integration is a durable skill across model and framework consolidations.
- Production guardrails (cost caps, observability, audit, evals) carry forward to whatever the 2027 stack is.
- Core patterns transfer to cloud, on-prem, and hybrid deployments.