MyBatis paged query, SQL Server 2008 query is slow

A business scenario that requires a union query:

The query is very slow and takes about 37 seconds:

Direct replication SQL in the database client execution, fast, it is known that the reason for MyBatis, on-line search, you can configure fetchsize= "500", but the test results are the same, re-view SQL, the return subquery and the merged query, are taken alias A, Replace the alias after union, re-test, paging query normal:

MyBatis paged query, SQL Server 2008 query is slow