Don't wait for ReadyForQuery after FATAL errors#765
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v0idpwn
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Mar 18, 2026
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| defp error_ready(s, _status, %Postgrex.Error{postgres: %{severity: severity}} = err, buffer) | ||
| when severity in ["FATAL", "PANIC"] do | ||
| %{connection_id: connection_id} = s | ||
| {:disconnect, %{err | connection_id: connection_id}, %{s | buffer: buffer}} | ||
| end | ||
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| defp error_ready(s, status, %Postgrex.Error{} = err, buffer) do |
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I don't love that this is called error_ready but couldn't come up with a better name for the new implementation.
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I think maybe instead of returning {:disconnect, ...} immediately, it should wait for ReadyForQuery or for the socket closed to be closed (which is what libpq does, if I'm not mistaken), then return the error.
When PostgreSQL sends a FATAL or PANIC ErrorResponse, it closes the connection immediately without sending ReadyForQuery. Postgrex unconditionally waited for ReadyForQuery, which would hit tcp_closed and return a generic disconnect error, discarding the original FATAL error.
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v0idpwn
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I think SimpleConnection may need some error handling tweak to handle this too. I'll look into that tomorrow 🙏🏻
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When PostgreSQL sends a FATAL or PANIC ErrorResponse, it closes the connection immediately without sending ReadyForQuery.
Postgrex unconditionally waited for ReadyForQuery, which would hit tcp_closed and return a generic disconnect error, discarding the original error message.
I've included in the PR a test that would fail with the previous implementation. The query would return a