我需要加快在我的应用程序中执行12个查询。 我从一个普通的foreach来Parallel.ForEach切换。 但有时我得到一个错误说“ExecuteReader需要开放和可用连接的连接的当前状态为连接。” 这是我的理解是,因为许多12个查询使用相同的InitialCatalog,没有真正为12的新的连接,可能是什么问题? 我怎样才能解决这个问题? “SQL”的类型列表“SQL” - 一类只是一个字符串名称,字符串connectiona和查询的列表。 下面是代码:
/// <summary>
/// Connects to SQL, performs all queries and stores results in a list of DataTables
/// </summary>
/// <returns>List of data tables for each query in the config file</returns>
public List<DataTable> GetAllData()
{
Stopwatch sw = new Stopwatch();
sw.Start();
List<DataTable> data = new List<DataTable>();
List<Sql> sql=new List<Sql>();
Sql one = new Sql();
one.connection = "Data Source=XXX-SQL1;Initial Catalog=XXXDB;Integrated Security=True";
one.name = "Col1";
one.queries.Add("SELECT Name FROM [Reports]");
one.queries.Add("SELECT Other FROM [Reports2]");
sql.Add(one);
Sql two = new Sql();
two.connection = "Data Source=XXX-SQL1;Initial Catalog=XXXDB;Integrated Security=True";
two.name = "Col2";
two.queries.Add("SELECT AlternateName FROM [Reports1]");
sql.Add(two);
Sql three = new Sql();
three.connection = "Data Source=YYY-SQL2;Initial Catalog=YYYDB;Integrated Security=True";
three.name = "Col3";
three.queries.Add("SELECT Frequency FROM Times");
sql.Add(three);
try
{
// ParallelOptions options = new ParallelOptions();
//options.MaxDegreeOfParallelism = 3;
// Parallel.ForEach(sql, options, s =>
Parallel.ForEach(sql, s =>
//foreach (Sql s in sql)
{
foreach (string q in s.queries)
{
using (connection = new SqlConnection(s.connection))
{
connection.Open();
DataTable dt = new DataTable();
dt.TableName = s.name;
command = new SqlCommand(q, connection);
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = command;
adapter.Fill(dt);
//adapter.Dispose();
lock (data)
{
data.Add(dt);
}
}
}
}
);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString(), "GetAllData error");
}
sw.Stop();
MessageBox.Show(sw.Elapsed.ToString());
return data;
}
下面是我做的,你需要的SQL类:
/// <summary>
/// Class defines a SQL connection and its respective queries
/// </summary>
public class Sql
{
/// <summary>
/// Name of the connection/query
/// </summary>
public string name { get; set; }
/// <summary>
/// SQL Connection string
/// </summary>
public string connection { get; set; }
/// <summary>
/// List of SQL queries for a connection
/// </summary>
public List<string> queries = new List<string>();
}