We recently observed performance issues after migrating varchar fields in DB to nvarchar. Prepared statements generated actually reserves 4000 instead of length of column. This is causing heaving memory usage in server side. How can we optimize hibernate not to use max length for nvarchar fields?

eg: exec sp_prepexec @p1 output,N'@P0 nvarchar(4000),@P1 nvarchar(4000),@P2 nvarchar(4000),@P3 nvarchar(4000),@P4 nvarchar(4000),@P5 nvarchar(4000),@P6 nvarchar(4000),@P7 nvarchar(4000),@P8 nvarchar(4000)',N'select ********

Why do you think that's due to Hibernate? It looks more like an SQL Server JDBC driver issue. Try to investigate it thoroughly.