NHibernate的添加選項進行查詢

Question

最近我有生成的SQL與NHibernate的性能問題，在

Nhibernate generate plain sql query instead of execution statement

說明我還發現，描述從一個只有傑夫·阿特伍德類似經歷一個鏈接

http://legeronline.blogspot.ca/2009/03/evils-of-slow-paramaterized-query-plans.html

有誰知道是否有無論如何向Nhibernate添加「優化Uknown」選項？

Answer 1

• 你可以看看延長MsSqlDialect或
• 實施IConnectionProvider注入自己commandwrapper它增加時ExecuteReader()叫

Answer 2

這個例子提示更是一個有點冗長：

public class OptionInterceptor: EmptyInterceptor 
{ 
    public override SqlString OnPrepareStatement(SqlString sql) 
    { 
     var parameters = sql.GetParameters(); 
     var paramCount = parameters.Count(); 

     if (paramCount == 0) 
      return sql; 

     string optionString = " OPTION (OPTIMIZE FOR ("; 

     for (var i = 0; i < paramCount; i++) 
     { 
      var comma = i > 0 ? "," : string.Empty; 
      optionString = optionString + comma + "@p" + i + " UNKNOWN"; 
     } 

     optionString = optionString + "))"; 

     var builder = new SqlStringBuilder(sql); 

     builder.Add(optionString); 

     return builder.ToSqlString(); 
    } 
} 

然後在你的SessionFactory /初始化：

configuration.ExposeConfiguration(x => 
    { 
     x.SetInterceptor(new OptionInterceptor()); 
    });