diff --git a/config/database.yml.example b/config/database.yml.example
index 727b4d89b..6b0849602 100644
--- a/config/database.yml.example
+++ b/config/database.yml.example
@@ -10,6 +10,12 @@ production:
   password: ""
   # Use "utf8" instead of "utfmb4" for MySQL prior to 5.7.7
   encoding: utf8mb4
+  variables:
+    # Recommended `transaction_isolation` for MySQL to avoid concurrency issues is
+    # `READ-COMMITTED`.
+    # In case of MySQL lower than 8, the variable name is `tx_isolation`.
+    # See https://www.redmine.org/projects/redmine/wiki/MySQL_configuration
+    transaction_isolation: "READ-COMMITTED"
 
 development:
   adapter: mysql2
@@ -19,6 +25,8 @@ development:
   password: ""
   # Use "utf8" instead of "utfmb4" for MySQL prior to 5.7.7
   encoding: utf8mb4
+  variables:
+    transaction_isolation: "READ-COMMITTED"
 
 # Warning: The database defined as "test" will be erased and
 # re-generated from your development database when you run "rake".
@@ -31,6 +39,8 @@ test:
   password: ""
   # Use "utf8" instead of "utfmb4" for MySQL prior to 5.7.7
   encoding: utf8mb4
+  variables:
+    transaction_isolation: "READ-COMMITTED"
 
 # PostgreSQL configuration example
 #production: