pldbgapi

pldebugger : server-side support for debugging PL/pgSQL functions

Overview

Packages

Source

Install

Make sure PGDG repo available:

pig repo add pgdg -u    # add pgdg repo and update cache

Install this extension with pig:

pig install pldebugger;		# install via package name, for the active PG version
pig install pldbgapi;		# install by extension name, for the current active PG version

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

Config this extension to shared_preload_libraries:

shared_preload_libraries = 'pldbgapi';

Create this extension with:

CREATE EXTENSION pldbgapi;

Usage

Sources: repo README, v1.10 release, extension control

pldbgapi provides a server-side API for interactive debugging of PL/pgSQL functions. It is typically used through a GUI client such as pgAdmin.

CREATE EXTENSION pldbgapi;

Debugging with pgAdmin

The primary way to use the debugger is through pgAdmin’s graphical interface:

• Direct Debugging: Right-click a function and select “Debug” to execute and step through it immediately
• Global Breakpoints: Select “Set Global Breakpoint” on a function, then wait for another session (e.g., a web application) to call that function – the debugger will intercept the call and allow in-context debugging

Debugging Capabilities

When connected through a debug client, you can:

• Set breakpoints on specific lines in PL/pgSQL functions
• Step through code line by line (step into, step over, step out)
• Inspect variables and their current values at each step
• View the call stack for nested function calls
• Continue execution to the next breakpoint

Architecture

The debugging system has three components:

1. Client GUI (pgAdmin) – displays source code, variables, and stack
2. Target Backend – the session executing the PL/pgSQL code being debugged
3. Debugging Proxy – coordinates between the client and target via a dedicated connection

Supported Languages

The debugger works with PL/pgSQL functions and procedures. It requires the pldbgapi extension to be created in each database where debugging is needed.

Caveats

• The package name is pldebugger, while the extension created in SQL is pldbgapi; the catalog tracks package version 1.10 for PostgreSQL 14 through 18.
• The v1.10 upstream release is a PostgreSQL compatibility update and does not document a new user-facing SQL API or debugging workflow.
• Upstream troubleshooting says shared_preload_libraries = '$libdir/plugin_debugger' must be configured and PostgreSQL restarted. Missing or incorrect preload prevents global breakpoints and can also prevent pldbgapi SQL from loading on some platforms.