From a6f20205a37ac5887cf47eaba403974a95f9cc3f Mon Sep 17 00:00:00 2001
From: Dohan Kim <hodoli2776@paran.com>
Date: Wed, 22 Jan 2025 21:21:54 +0900
Subject: [PATCH] Call disconnect on protocol when reconnecting in Replication
 connection  (#726)

---
 lib/postgrex/replication_connection.ex | 10 ++++++++++
 lib/postgrex/simple_connection.ex      | 11 +++++++++++
 2 files changed, 21 insertions(+)

diff --git a/lib/postgrex/replication_connection.ex b/lib/postgrex/replication_connection.ex
index 6a5ec734..3354f17c 100644
--- a/lib/postgrex/replication_connection.ex
+++ b/lib/postgrex/replication_connection.ex
@@ -490,12 +490,22 @@ defmodule Postgrex.ReplicationConnection do
     {:keep_state, s, {:next_event, :internal, {:connect, :backoff}}}
   end
 
+  def handle_event(:internal, {:connect, :reconnect}, @state, %{protocol: protocol} = state)
+      when protocol != nil do
+    Protocol.disconnect(:reconnect, protocol)
+    {:keep_state, %{state | protocol: nil}, {:next_event, :internal, {:connect, :init}}}
+  end
+
   def handle_event(:internal, {:connect, _info}, @state, %{state: {mod, mod_state}} = s) do
     case Protocol.connect(opts()) do
       {:ok, protocol} ->
         maybe_handle(mod, :handle_connect, [mod_state], %{s | protocol: protocol})
 
       {:error, reason} ->
+        Logger.error(
+          "#{inspect(pid_or_name())} (#{inspect(mod)}) failed to connect to Postgres: #{Exception.format(:error, reason)}"
+        )
+
         if s.auto_reconnect do
           {:keep_state, s, {{:timeout, :backoff}, s.reconnect_backoff, nil}}
         else
diff --git a/lib/postgrex/simple_connection.ex b/lib/postgrex/simple_connection.ex
index 0f411341..eaef1f8e 100644
--- a/lib/postgrex/simple_connection.ex
+++ b/lib/postgrex/simple_connection.ex
@@ -362,6 +362,10 @@ defmodule Postgrex.SimpleConnection do
         end
 
       {:error, reason} ->
+        Logger.error(
+          "#{inspect(pid_or_name())} (#{inspect(mod)}) failed to connect to Postgres: #{Exception.format(:error, reason)}"
+        )
+
         if state.auto_reconnect do
           {:keep_state, state, {{:timeout, :backoff}, state.reconnect_backoff, nil}}
         else
@@ -466,6 +470,13 @@ defmodule Postgrex.SimpleConnection do
     end
   end
 
+  defp pid_or_name do
+    case Process.info(self(), :registered_name) do
+      {:registered_name, atom} when is_atom(atom) -> atom
+      _ -> self()
+    end
+  end
+
   defp opts(mod), do: Process.get(mod)
 
   defp put_opts(mod, opts), do: Process.put(mod, opts)