From ee9adcbf0672a00d765dc1bdf2e0d8bc2205c518 Mon Sep 17 00:00:00 2001
From: Oleksii Sholik <oleksii@sholik.dev>
Date: Sat, 30 Sep 2023 23:40:26 +0300
Subject: [PATCH] Leave notes to check error behaviour of epgsql conn resources

---
 .../lib/electric/postgres/extension/schema_loader/epgsql.ex      | 1 +
 components/electric/lib/electric/replication/postgres/client.ex  | 1 +
 components/electric/lib/electric/replication/postgres_manager.ex | 1 +
 .../electric/lib/electric/replication/shapes/shape_request.ex    | 1 +
 4 files changed, 4 insertions(+)

diff --git a/components/electric/lib/electric/postgres/extension/schema_loader/epgsql.ex b/components/electric/lib/electric/postgres/extension/schema_loader/epgsql.ex
index dce3c11b4e..85b64c2dda 100644
--- a/components/electric/lib/electric/postgres/extension/schema_loader/epgsql.ex
+++ b/components/electric/lib/electric/postgres/extension/schema_loader/epgsql.ex
@@ -93,6 +93,7 @@ defmodule Electric.Postgres.Extension.SchemaLoader.Epgsql do
         # "ALTER SUBSCRIPTION ... REFRESH is not allowed for disabled subscriptions"
         # ignore this as it's due to race conditions with the rest of the system
         {:error, {:error, :error, "55000", :object_not_in_prerequisite_state, _, _}} ->
+          # TODO: Check if this leaves the connection in an unusable state
           Logger.warning("Unable to refresh DISABLED subscription #{name}")
           :ok
 
diff --git a/components/electric/lib/electric/replication/postgres/client.ex b/components/electric/lib/electric/replication/postgres/client.ex
index 9dd974ba39..d4dff63763 100644
--- a/components/electric/lib/electric/replication/postgres/client.ex
+++ b/components/electric/lib/electric/replication/postgres/client.ex
@@ -31,6 +31,7 @@ defmodule Electric.Replication.Postgres.Client do
   end
 
   def start_subscription(conn, name) do
+    # TODO: check if an error return here leaves conn in an unusable state
     with {:ok, _, _} <- squery(conn, ~s|ALTER SUBSCRIPTION "#{name}" ENABLE|),
          {:ok, _, _} <-
            squery(
diff --git a/components/electric/lib/electric/replication/postgres_manager.ex b/components/electric/lib/electric/replication/postgres_manager.ex
index 0c89298048..8f060ac75c 100644
--- a/components/electric/lib/electric/replication/postgres_manager.ex
+++ b/components/electric/lib/electric/replication/postgres_manager.ex
@@ -188,6 +188,7 @@ defmodule Electric.Replication.PostgresConnectorMng do
     )
 
     ConnectionPool.checkout!(origin, fn conn ->
+      # TODO: check if an error return here leaves conn in an unusable state
       with {:ok, versions} <- Extension.migrate(conn),
            {:ok, _} <-
              Client.create_subscription(conn, subscription, publication, electric_connection),
diff --git a/components/electric/lib/electric/replication/shapes/shape_request.ex b/components/electric/lib/electric/replication/shapes/shape_request.ex
index d51fb0a53c..dee0cc917a 100644
--- a/components/electric/lib/electric/replication/shapes/shape_request.ex
+++ b/components/electric/lib/electric/replication/shapes/shape_request.ex
@@ -154,6 +154,7 @@ defmodule Electric.Replication.Shapes.ShapeRequest do
           {:ok, count, records}
 
         {:error, _} = error ->
+          # TODO: check if this leaves conn in an usuable state
           error
       end
     end