Contents

• pg_re2 Postgres Extension
  • Building
  • Usage
  • Dependencies
  • Copyright and License

pg_re2 Postgres Extension

This library contains a single PostgreSQL extension, re2, which provides ClickHouse-compatible regular expression functions powered by re2:

try=# create extension re2;
CREATE EXTENSION

try=# SELECT re2match('hello world', 'h.*o');
 re2match 
----------
 t
(1 row)

Building

To build pg_re2, install the re2 library then just do this:

make
make installcheck
make install

If you encounter an error such as:

"Makefile", line 8: Need an operator

You need to use GNU make, which may well be installed on your system as gmake:

gmake
gmake install
gmake installcheck

If you encounter an error such as:

make: pg_config: Command not found

Be sure that you have pg_config installed and in your path. If you used a package management system such as RPM to install PostgreSQL, be sure that the -devel package is also installed. If necessary tell the build process where to find it:

env PG_CONFIG=/path/to/pg_config make && make installcheck && make install

If you counter an error such as:

src/re2_wrapper.cpp:14:10: fatal error: 're2/re2.h' file not found

You either need to install re2 or tell the compiler where to find it. If, for example, you installed the Homebrew re2, try:

make CPPFLAGS=-I/opt/homebrew/include \
     CFLAGS=-I/opt/homebrew/include \
     LDFLAGS=-L/opt/homebrew/lib

If you encounter an error such as:

ERROR:  must be owner of database regression

You need to run the test suite using a super user, such as the default “postgres” super user:

make installcheck PGUSER=postgres

To install the extension in a custom prefix on PostgreSQL 18 or later, pass the prefix argument to install (but no other make targets):

make install prefix=/usr/local/extras

Then ensure that the prefix is included in the following postgresql.conf parameters:

extension_control_path = '/usr/local/extras/postgresql/share:$system'
dynamic_library_path   = '/usr/local/extras/postgresql/lib:$libdir'

Usage

Once re2 is installed, you can add it to a database by connecting to a database as a super user and running:

CREATE EXTENSION re2;

If you want to install re2 and all of its supporting objects into a specific schema, use the SCHEMA clause to specify the schema, like so:

CREATE SCHEMA env;
CREATE EXTENSION re2 SCHEMA env;

Dependencies

The re2 extension requires PostgreSQL 16 or higher, re2, and the C standard library, <stdlib.h>.

Copyright and License

Copyright © 2026 ClickHouse

This module is free software; you can redistribute it and/or modify it under the PostgreSQL License.

Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies.

In no event shall ClickHouse be liable to any party for direct, indirect, special, incidental, or consequential damages, including lost profits, arising out of the use of this software and its documentation, even if ClickHouse has been advised of the possibility of such damage.

ClickHouse specifically disclaim any warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. The software provided hereunder is on an “as is” basis, and ClickHouse have no obligations to provide maintenance, support, updates, enhancements, or modifications.