diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/schema/MySql.java b/gerrit-server/src/main/java/com/google/gerrit/server/schema/MySql.java
index 8c46732ef8..308cec8ec6 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/schema/MySql.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/schema/MySql.java
@@ -47,6 +47,10 @@ class MySql extends BaseDataSourceType {
 
   @Override
   public boolean usePool() {
+    // MySQL has given us trouble with the connection pool,
+    // sometimes the backend disconnects and the pool winds
+    // up with a stale connection. Fortunately opening up
+    // a new MySQL connection is usually very fast.
     return false;
   }
 }
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