What is PostgreSQL logical decoding and its applications?

Logical decoding extracts changes from WAL in a user-friendly format.

Applications:
• Change data capture (CDC)
• Real-time analytics
• Data synchronization
• Audit logging

Output Plugins:
• test_decoding (built-in)
• wal2json
• pgoutput (for logical replication)

Setup:

-- Enable logical replication
wal_level = logical
max_replication_slots = 4

-- Create replication slot
SELECT pg_create_logical_replication_slot('my_slot', 'test_decoding');