Add indexes on workflow_edges and steps tables (#2849)

* Add indexes to foreign keys

- Attempting to resolve slow editor loading issues

* Update CHANGELOG

* Make index additions idempotent

* Remove conflict artifact from CHANGELOG.md

CHANGELOG.md

@@ -26,6 +26,9 @@ and this project adheres to
   [#2718](https://github.com/OpenFn/lightning/issues/2718)
 - Temporary instrumentation for JobEditor to help identify performance issues.
   [#2617](https://github.com/OpenFn/lightning/issues/2617)
+- Indexes to foreign keys on `workflow_edges` and `steps` tables to try and
+  alleviate slow loading of the job editor.
+  [#2617](https://github.com/OpenFn/lightning/issues/2617)
 
 ### Changed
 

priv/repo/migrations/20250122110318_index_workflow_id_on_workflow_edges.exs

@@ -0,0 +1,7 @@
+defmodule Lightning.Repo.Migrations.IndexWorkflowIdOnWorkflowEdges do
+  use Ecto.Migration
+
+  def change do
+    create_if_not_exists index(:workflow_edges, [:workflow_id])
+  end
+end

priv/repo/migrations/20250122110504_index_job_id_on_steps.exs

@@ -0,0 +1,7 @@
+defmodule Lightning.Repo.Migrations.IndexJobIdOnSteps do
+  use Ecto.Migration
+
+  def change do
+    create_if_not_exists index(:steps, [:job_id])
+  end
+end