From 91a682c372ffb1c3e61d13e25b51455fb2decc68 Mon Sep 17 00:00:00 2001
From: Kazuma Watanabe <watassbass@gmail.com>
Date: Sun, 11 Feb 2024 16:43:15 +0900
Subject: [PATCH] Add "Nested Transactions" section

---
 README.adoc | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/README.adoc b/README.adoc
index 47652a5..f0971af 100644
--- a/README.adoc
+++ b/README.adoc
@@ -847,6 +847,28 @@ else
 end
 ----
 
+=== Nested Transactions [[nested-transactions]]
+
+Use `requires_new: true` if you want to avoid nested transactions unintentionally becoming part of the parent transaction.
+`joinable: false` is a private API and should not be used. If used, serious side effects may occur, such as `after_commit` not working properly.
+
+[source,ruby]
+----
+# bad
+ActiveRecord::Base.transaction(requires_new: true, joinable: false) do
+  ActiveRecord::Base.transaction do
+    # ...
+  end
+end
+
+# good
+ActiveRecord::Base.transaction(requires_new: true) do
+  ActiveRecord::Base.transaction(requires_new: true) do
+    # ...
+  end
+end
+----
+
 == Models: Active Record Queries [[activerecord-queries]]
 
 === Avoid Interpolation [[avoid-interpolation]]