plluau

Overview

Version

Install

You can install pllua directly. First, make sure the PGDG and PIGSTY repositories are added and enabled:

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

Install the extension using pig or apt/yum/dnf:

pig install pllua;          # Install for current active PG version

pig ext install -y pllua -v 18  # PG 18
pig ext install -y pllua -v 17  # PG 17
pig ext install -y pllua -v 16  # PG 16
pig ext install -y pllua -v 15  # PG 15
pig ext install -y pllua -v 14  # PG 14

dnf install -y pllua_18       # PG 18
dnf install -y pllua_17       # PG 17
dnf install -y pllua_16       # PG 16
dnf install -y pllua_15       # PG 15
dnf install -y pllua_14       # PG 14

apt install -y postgresql-18-pllua   # PG 18
apt install -y postgresql-17-pllua   # PG 17
apt install -y postgresql-16-pllua   # PG 16
apt install -y postgresql-15-pllua   # PG 15
apt install -y postgresql-14-pllua   # PG 14

Create Extension:

CREATE EXTENSION plluau;

Usage

plluau: Lua as an untrusted procedural language

plluau is the untrusted variant of pllua, allowing Lua functions to access the filesystem, load arbitrary modules, and perform operations restricted in the trusted version.

CREATE EXTENSION plluau;

Create Functions

CREATE FUNCTION read_file(path text) RETURNS text LANGUAGE plluau AS $$
  local f = io.open(path, "r")
  if f then
    local content = f:read("*a")
    f:close()
    return content
  end
  return nil
$$;

Differences from pllua (Trusted)

Same API as pllua

plluau shares the same SPI interface, trigger support, set-returning functions, and data type handling as pllua. All SPI functions (spi.execute, spi.prepare, spi.rows), coroutine-based set returns, and trigger functions work identically.

CREATE FUNCTION run_command(cmd text) RETURNS text LANGUAGE plluau AS $$
  local handle = io.popen(cmd)
  local result = handle:read("*a")
  handle:close()
  return result
$$;

Initialization

Configure via GUC (superuser only):

SET pllua.on_untrusted_init = 'myvar = {}';

Only superusers can create plluau functions due to the unrestricted access it provides.