pg_clickhouse

pg_clickhouse : Interfaces to query ClickHouse databases from PostgreSQL

Overview

Packages

Source

pig build pkg pg_clickhouse;		# build rpm/deb

Install

Make sure PGDG and PIGSTY repo available:

pig repo add pgsql -u   # add both repo and update cache

Install this extension with pig:

pig install pg_clickhouse;		# install via package name, for the active PG version

pig install pg_clickhouse -v 18;   # install for PG 18
pig install pg_clickhouse -v 17;   # install for PG 17
pig install pg_clickhouse -v 16;   # install for PG 16
pig install pg_clickhouse -v 15;   # install for PG 15
pig install pg_clickhouse -v 14;   # install for PG 14

Config this extension to shared_preload_libraries:

shared_preload_libraries = 'pg_clickhouse';

Create this extension with:

CREATE EXTENSION pg_clickhouse;

Usage

pg_clickhouse: ClickHouse integration for PostgreSQL

pg_clickhouse enables analytics queries on ClickHouse directly from PostgreSQL without SQL rewriting. It supports PostgreSQL 13+ and ClickHouse v23+.

Create the Extension

CREATE EXTENSION pg_clickhouse;

Or into a specific schema:

CREATE SCHEMA env;
CREATE EXTENSION pg_clickhouse SCHEMA env;

Query Pushdown

The extension automatically pushes down analytical queries to ClickHouse for execution, providing significant performance improvements. For example, TPC-H benchmarks show:

• Query 1: 268ms (vs 4,693ms on standard PostgreSQL)
• Query 6: 53ms (vs 764ms on standard PostgreSQL)

When query pushdown is active, ClickHouse handles execution directly, avoiding data transfer overhead for complex analytical workloads.