| PostgreSQL pl/pgsql Debugger API | |
| ================================ | |
| This module is a set of shared libraries which implement an API for debugging | |
| pl/pgsql functions on PostgreSQL 8.4 and above. The pgAdmin project | |
| (http://www.pgadmin.org/) provides a client user interface as part of pgAdmin | |
| III v1.10.0 and above, and pgAdmin 4. | |
| If you wish to debug functions on PostgreSQL 8.4, 9.0 or 9.1, please checkout | |
| the PRE-9_2 branch from GIT. | |
| If you wish to debug functions on PostgreSQL 8.2 or 8.3, please checkout the | |
| PRE_8_4_SERVER branch from CVS. | |
| Installation | |
| ------------ | |
| - Copy this directory to contrib/ in your PostgreSQL source tree. | |
| - Run 'make; make install' | |
| - Edit your postgresql.conf file, and modify the shared_preload_libraries config | |
| option to look like: | |
| shared_preload_libraries = '$libdir/plugin_debugger' | |
| - Restart PostgreSQL for the new setting to take effect. | |
| - Run the following command in the database or databases that you wish to | |
| debug functions in: | |
| CREATE EXTENSION pldbgapi; | |
| (on server versions older than 9.1, you must instead run the pldbgapi--1.1.sql | |
| script directly using psql). | |
| Usage | |
| ----- | |
| Connect pgAdmin to the database containing the functions you wish to debug. | |
| Right-click the function to debug, and select Debugging->Debug to execute and | |
| debug the function immediately, or select Debugging->Set Global Breakpoint to | |
| set a breakpoint on the function. This will cause the debugger to wait for | |
| another session (such as a backend servicing a web app) to execute the function | |
| and allow you to debug in-context. | |
| For further information, please see the pgAdmin documentation. | |
| Troubleshooting | |
| --------------- | |
| The majority of problems we've encountered with the plugin are caused by | |
| failing to add (or incorrectly adding) the debugger plugin library to the | |
| shared_preload_libraries configuration directive in postgresql.conf (following | |
| which, the server *must* be restarted). This will prevent global breakpoints | |
| working on all platforms, and on some (notably Windows) may prevent the | |
| pldbgapi.sql script from executing correctly. | |
| Architecture | |
| ------------ | |
| The debugger consists of three parts: | |
| 1. The client. This is typically a GUI displays the source code, current | |
| stack frame, variables etc, and allows the user to set breakpoints and | |
| step throught the code. The client can reside on a different host than | |
| the database server. | |
| 2. The target backend. This is the backend that runs the code being debugged. | |
| The plugin_debugger.so library must be loaded into the target backend. | |
| 3. Debugging proxy. This is another backend process that the client is | |
| connected to. The API functions, pldbg_* in pldbgapi.so library, are | |
| run in this backend. | |
| The client is to connected to the debugging proxy using a regular libpq | |
| connection. When a debugging session is active, the proxy is connected | |
| to the target via a socket. The protocol between the proxy and the target | |
| backend is not visible to others, and is subject to change. The pldbg_* | |
| API functions form the public interface to the debugging facility. | |
| debugger client *------ libpq --------* Proxy backend | |
| (pgAdmin) * | |
| | | |
| pldebugger socket connection | |
| | | |
| * | |
| application client *----- libpq -------* Target backend | |
| Licence | |
| ------- | |
| The pl/pgsql debugger API is released under the Artistic Licence v2.0. | |
| https://opensource.org/licenses/artistic-license-2.0 | |
| Copyright (c) 2004-2022 EnterpriseDB Corporation. All Rights Reserved. | |
| Contact | |
| ------- | |
| For support, please email the pgAdmin support mailing list. See | |
| http://www.pgadmin.org/support/ | |
| for more details. | |