My blog was almost dead last weekend because which encountered get 28 error in mysql. That's why I was seeking how come this error occurred in my blog. After a few hours, I found that query cache in mysql exceed the limited amount due to struct function of Coldfusion.
As the outcome of troubleshooting, using Struct in coldfusion may leak database memory and should make clear all value in Struct after using.
In mysql, Coldfusion create the blank temporary table for struct function when we using it. After assigning value into struct by developers, Coldfusion also adding value from struct into the blank temporary table.
For every single request, Coldfusion always create the single blank temporary table for struct. For million requests, Coldfusion will also do like that? :)