Senior LevelPostgreSQL
How does the Citus extension transform PostgreSQL into a distributed scale-out database?
❓ Interview Prompt: Explain Citus extension, Coordinator node, Worker nodes, Distributed Tables, Reference Tables, and distributed query execution.
Citus is an open-source extension that transforms PostgreSQL into a distributed, horizontally scaled database cluster:
Citus Architecture:
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Coordinator Node: Receives application SQL queries, plans distributed query trees, and coordinates worker nodes.
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Distributed Tables: Tables partitioned across worker nodes using a distribution column.
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Reference Tables: Replicated tables present on ALL worker nodes for fast local joins.
Code Implementation Example
sql
-- Enable Citus extension
CREATE EXTENSION IF NOT EXISTS citus;
-- Distribute orders table across Citus worker nodes by customer_id
SELECT create_distributed_table('orders', 'customer_id');💡Distributing tables across Citus cluster worker nodes.
🎯 Interview Key Takeaway
Use Citus for scaling out multi-tenant or real-time analytics databases across a cluster of PostgreSQL nodes.
#Citus#Distributed Database#Sharding#Scale-Out#Senior
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