Replication — Complete Guide
Replication — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of MySQL Tutorial on Toolliyo Academy.
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MySQL Tutorial · Lesson 76 of 100
Replication
Basics ✓ → Advanced
Advanced · 2 — Production · ~10 min · MySQL — Advanced MySQL
What is this?
MySQL replication copies changes from primary (source) to replica (binary log → apply thread). Async by default; semi-sync optional for tighter durability.
Why should you care?
Backups from replica avoid locking checkout on primary; also foundation for read scale and DR.
See it live — copy this example
Run in MySQL Workbench or the mysql CLI.
-- On primary: verify binary log
SHOW BINARY LOG STATUS;
SHOW REPLICA STATUS\G
-- On replica (MySQL 8 terminology):
-- CHANGE REPLICATION SOURCE TO ... (configured by DBA)What happened?
- Binary log records writes on primary.
- Replica IO thread pulls events; SQL thread applies.
- SHOW REPLICA STATUS shows Seconds_Behind_Source lag metric.
Practice next
- Read replication docs — local two-instance setup is advanced lab.
- On managed RDS: check replication panel for lag.
- SHOW BINARY LOG STATUS on primary if permitted.
- Identify read-only routes in app using replica host.
- Study GTID-based failover vs file+position.
Remember
Binlog streams changes to replicas. Lag metric monitors freshness. Replicas for read scale and DR.
DataFlow RDS replica
Primary in Mumbai; async replica for reporting — 2s lag acceptable.
Outcome: Heavy BI queries off primary.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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