PL/Ruby is a procedural-language handler that lets you write database functions in Ruby, stored and executed inside PostgreSQL. You get the expressiveness of Ruby and its standard library with the full power of a native PostgreSQL function: plain functions, set-returning functions, triggers, event triggers, and procedures with transaction control.

CREATE EXTENSION plruby;

CREATE FUNCTION hello(text) RETURNS text LANGUAGE plruby AS $$
    "Hello, #{args[0]}!"
$$;

SELECT hello('world');   -- Hello, world!

Note

PL/Ruby embeds an MRI Ruby interpreter in the backend. It targets PostgreSQL 11-18 and Ruby 3.x, installs as a first-class CREATE EXTENSION, and mirrors the feature set of PL/php with a large set of PL/Perl- and PL/Tcl-inspired capabilities.

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Features

🧩 Scalars, arrays, composites	Arguments arrive as native Ruby values: Integer, Float, true/false, String, nested Array, and composite/record types as Hash.
🔁 Set-returning functions	RETURNS SETOF / RETURNS TABLE with return_next.
⚡ Triggers	Row & statement triggers via $_TD (with 'SKIP' / 'MODIFY').
📣 Event triggers	Back CREATE EVENT TRIGGER with RETURNS event_trigger.
🗄️ Database access (SPI)	spi_exec, spi_fetch_row, spi_processed, spi_status, spi_rewind, and result column metadata (spi_colnames / spi_coltypes / spi_coltypmods).
🌊 Cursor streaming	spi_query (block or handle), spi_fetchrow, spi_cursor_close, Cursor#each. Consume large results without materializing them.
📝 Prepared statements	spi_prepare / spi_exec_prepared / spi_query_prepared / spi_freeplan.
🔐 Transaction control	spi_commit / spi_rollback in procedures, plus subtransaction blocks.
🧰 Utilities	quote_literal / quote_nullable / quote_ident, elog, session-shared $_SHARED, and per-function $_SD.
📦 Session setup	Anonymous DO blocks, plruby_modules autoloading, and a plruby.start_proc hook.
🔄 Transforms	jsonb_plruby, hstore_plruby, and ltree_plruby: functions declared TRANSFORM FOR TYPE exchange native Ruby Hashes/Arrays with jsonb, hstore, and ltree.

See the language reference for the full API, the cookbook for tested recipes, and the PL/Perl and PL/Tcl comparisons for feature-by-feature detail.

Examples

A set-returning function

CREATE FUNCTION squares(lim integer)
RETURNS TABLE(n integer, square integer) LANGUAGE plruby AS $$
    (1..lim).each do |i|
        n = i
        square = i * i
        return_next
    end
$$;

SELECT * FROM squares(3);   -- (1,1), (2,4), (3,9)

Querying the database with a prepared plan

CREATE FUNCTION lookup(int) RETURNS text LANGUAGE plruby AS $$
    plan = spi_prepare('select name from things where id = $1', 'int4')
    row  = spi_fetch_row(spi_exec_prepared(plan, args[0]))
    spi_freeplan(plan)
    row['name']
$$;

A row trigger that transforms data

CREATE FUNCTION uppercase_name() RETURNS trigger LANGUAGE plruby AS $$
    $_TD['new']['name'] = $_TD['new']['name'].upcase
    'MODIFY'
$$;

Requirements

• PostgreSQL 11 or newer (tested on 11-18; 18 recommended), with the server development files that provide pg_config.
• Ruby 3.x built as a shared library (ENABLE_SHARED=yes) with development headers. On Debian/Ubuntu, install ruby-dev.

Installation

make
sudo make install

Then, in a database:

CREATE EXTENSION plruby;

See INSTALL for details, and run the regression suite with make installcheck.

Security

Warning

PL/Ruby is an untrusted language. Ruby 3.0 and later have no sandbox ($SAFE and object tainting were removed in Ruby 3.0), so a PL/Ruby function can do anything the PostgreSQL server's operating-system user can: read and write files, open network connections, run shell commands, and so on.

The language is created without the TRUSTED attribute, so only superusers can install the extension or create PL/Ruby functions. Grant that ability only to roles you would trust with the server's OS account.

Documentation

• Language reference
• Cookbook: tested recipes
• Installation
• Changelog
• Feature comparison: PL/Ruby vs PL/php vs PL/Perl vs PL/Tcl
• PL/Ruby vs PL/Perl
• PL/Ruby vs PL/Tcl

License

PL/Ruby is licensed under the MIT License; see LICENSE.