BUG #19419: Cannot create custom functions using python3u

The following bug has been logged on the website:

Bug reference: 19419
Logged by: yafei wu
Email address: yfdd12138(at)gmail(dot)com
PostgreSQL version: 18.2
Operating system: windows
Description:

When I was installing the Windows version of PostgreSQL 18.2.1, I executed
the command "CREATE EXTENSION plpython3u;". Error message
[2026-02-26 23:35:02] [58P01] Error: Unable to load library
"D:/postgresql/PostgreSQL/18/lib/plpython3.dll": The specified module could
not be found.
[2026-02-26 23:35:02] At location: SQL statement "CREATE FUNCTION
plpython3_call_handler() RETURNS language_handler" [2026-02-26 23:35:02]
LANGUAGE c AS '$libdir/plpython3'"
[2026-02-26 23:35:02] Extension script file "plpython3u--1.0.sql", near line
3
When I placed the python313.dll file in the installation directory of Python
3.13 under the C:\Windows\System32 directory, and executed the command
"CREATE EXTENSION plpython3u;" Success, but when creating the Python custom
function, an error occurred.
[2026-02-26 23:45:01] An I/O error occurred while sending to the backend.
[2026-02-26 23:45:01] Received an irrecoverable error. The connection has
been damaged.