Postgres suddenly raise error '/usr/lib/libpq.5.dylib' (no such file)-CodePudding

when I run Django project or any code related to Postgres :

Referenced from: '/Users/mahmoudnasser/.local/share/virtualenvs/wyspp_backend-PwdII1PB/lib/python3.8/site-packages/psycopg2/_psycopg.cpython-38-darwin.so'
  Reason: tried: '/opt/homebrew/opt/postgresql/lib/libpq.5.dylib' (no such file), '/usr/local/lib/libpq.5.dylib' (no such file), '/usr/lib/libpq.5.dylib' (no such file)

I tried many solutions online but none of them worked.

Note: I use MacOS

CodePudding user response：

To solve this problem just run the following command:

sudo mkdir -p /usr/local/lib && sudo ln -s /opt/homebrew/opt/postgresql@14/lib/postgresql@14/libpq.5.dylib /usr/local/lib/libpq.5.dylib

CodePudding user response：

Something similar happened to me following a brew PostgreSQL upgrade. The solution to my problem was to delete my virtual environment, in my case .venv, and rerun:

python3 -m venv .venv
source .venv/bin/activate
python3 -m pip install -r requirements.txt

After that, I was able to start my application with no problem.

I think the issue was the result of an outdated dependency graph. Re-installing the dependencies with pip found the new version of Postgres and linked the libpq.5.dylib correctly.

Note, I was using the following psycopg2 dependency:

psycopg2-binary==2.9.3

For what it's worth, I am also on MacOS Monterey and this just happened in a second codebase on the same machine.

The exact error was:

ImportError: dlopen(/Users/username/dev/src/project/.venv/lib/python3.10/site-packages/psycopg2/_psycopg.cpython-310-darwin.so, 0x0002): Library not loaded: '/opt/homebrew/opt/postgresql/lib/libpq.5.dylib'
Referenced from: '/Users/username/dev/src/project/.venv/lib/python3.10/site-packages/psycopg2/_psycopg.cpython-310-darwin.so'
Reason: tried: '/opt/homebrew/opt/postgresql/lib/libpq.5.dylib' (no such file), '/usr/local/lib/libpq.5.dylib' (no such file), '/usr/lib/libpq.5.dylib' (no such file), '/opt/homebrew/Cellar/postgresql@14/14.5_4/lib/libpq.5.dylib' (no such file), '/usr/local/lib/libpq.5.dylib' (no such file), '/usr/lib/libpq.5.dylib' (no such file)