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Database

ClickHouse vs Postgres: Which MCP should you use?

🟡

ClickHouse

Columnar OLAP database for analytics

VS
🐘

Postgres

The world's most advanced open-source relational DB

TL;DR

ClickHouse is a columnar OLAP engine built for scanning billions of rows in milliseconds. Postgres is row-oriented OLTP — great for transactions and point reads. For dashboards over huge event tables, ClickHouse is often 100× faster; for user/order data, Postgres is the right tool.

ClickHouse: 2 winsPostgres: 4 wins2 ties
🟡

Pick ClickHouse

Pick ClickHouse when you scan billions of events for analytics, time-series, or product telemetry.

🐘

Pick Postgres

Pick Postgres when you serve an application's OLTP workload (users, orders, sessions).

Feature-by-feature comparison

Feature🟡ClickHouse🐘PostgresWinner
Storage layout
Columnar
Row-oriented
Tie
OLAP scan speed
Extreme (100x+ Postgres)
Adequate
A
OLTP / point updates
Weak (eventual merges)
Excellent
B
SQL compliance
Mostly, with extensions
Strict
B
Compression
10-100x
Moderate
A
Joins
Functional, limited planner
Mature optimizer
B
Real-time inserts
Async merges, batch-friendly
Row-at-a-time OK
Tie
Ops complexity
Higher (ZooKeeper/Keeper)
Lower
B

Storage layout

Tie

ClickHouse

Columnar

Postgres

Row-oriented

OLAP scan speed

A

ClickHouse

Extreme (100x+ Postgres)

Postgres

Adequate

OLTP / point updates

B

ClickHouse

Weak (eventual merges)

Postgres

Excellent

SQL compliance

B

ClickHouse

Mostly, with extensions

Postgres

Strict

Compression

A

ClickHouse

10-100x

Postgres

Moderate

Joins

B

ClickHouse

Functional, limited planner

Postgres

Mature optimizer

Real-time inserts

Tie

ClickHouse

Async merges, batch-friendly

Postgres

Row-at-a-time OK

Ops complexity

B

ClickHouse

Higher (ZooKeeper/Keeper)

Postgres

Lower

🟡

Best for

ClickHouse

  • OLAP scan speed: Extreme (100x+ Postgres)
  • Compression: 10-100x
🐘

Best for

Postgres

  • OLTP / point updates: Excellent
  • SQL compliance: Strict
  • Joins: Mature optimizer
  • Ops complexity: Lower

Migration path

Don't migrate — run both. Use Postgres for OLTP, replicate to ClickHouse for analytics via Debezium→Kafka→clickhouse-kafka-connect or PeerDB. If you must move a workload: re-model tables around queries (denormalize, pick MergeTree ORDER BY matching filters), accept that UPDATE/DELETE are heavy in ClickHouse.

Frequently asked questions

What is the main difference between ClickHouse and Postgres?

ClickHouse is a columnar OLAP engine built for scanning billions of rows in milliseconds. Postgres is row-oriented OLTP — great for transactions and point reads. For dashboards over huge event tables, ClickHouse is often 100× faster; for user/order data, Postgres is the right tool. In short: ClickHouse — Columnar OLAP database for analytics. Postgres — The world's most advanced open-source relational DB.

When should I pick ClickHouse over Postgres?

Pick ClickHouse when you scan billions of events for analytics, time-series, or product telemetry.

When should I pick Postgres over ClickHouse?

Pick Postgres when you serve an application's OLTP workload (users, orders, sessions).

Can I migrate from one to the other?

Don't migrate — run both. Use Postgres for OLTP, replicate to ClickHouse for analytics via Debezium→Kafka→clickhouse-kafka-connect or PeerDB. If you must move a workload: re-model tables around queries (denormalize, pick MergeTree ORDER BY matching filters), accept that UPDATE/DELETE are heavy in ClickHouse.

Do ClickHouse and Postgres both work with MCP-compatible AI agents?

Yes. Both have MCP servers installable via MCPizy (mcpizy install clickhouse and mcpizy install postgres). They work identically across Claude Code, Claude Desktop, Cursor, Windsurf, and any other MCP-compatible client. You can install both side by side and route queries in your agent's prompt.

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🟢VS🔥

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🐘VS🐬

Postgres vs MySQL

Both are mature open-source relational databases. Postgres has richer SQL (CTEs, window functions, JSON, arrays, extensions), stricter standards compliance, and better for complex analytics. MySQL is simpler, often faster on basic read-heavy workloads, and dominates WordPress/PHP ecosystems.

Install both with MCPizy

Not sure? Run both side by side — swap between them in your AI agent with a single config line.

$mcpizy install clickhouse && mcpizy install postgres
🟡Install ClickHouse🐘Install Postgres
Free to install. Swap between them in your agent config.