diff --git a/config/database.yml.example b/config/database.yml.example
index 727b4d89b..3acc5020c 100644
--- a/config/database.yml.example
+++ b/config/database.yml.example
@@ -10,6 +10,11 @@ production:
   password: ""
   # Use "utf8" instead of "utfmb4" for MySQL prior to 5.7.7
   encoding: utf8mb4
+  variables:
+    # You must set your MySQL server's `transaction_isolation` to
+    # `READ-COMMITTED`.
+    # See https://www.redmine.org/projects/redmine/wiki/MySQL_configuration
+    transaction_isolation: "READ-COMMITTED"
 
 development:
   adapter: mysql2
@@ -19,6 +24,8 @@ 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 +38,8 @@ 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: