我有一个c#应用程序正在从一个数据库中取数据,进行必要的转换,并将数据插入到另一个数据库的表中。我通过将我的源数据插入到队列中,然后处理队列以将数据插入到目标表中来完成此操作。我有两个独立的线程来读取源数据并写入目标数据。阅读线程的运行速度比写入线程快得多,所以我的队列填满很快。从ConcurrentQueue插入多行到SQL Server表中
正如您在阅读线程中所看到的,我使用SqlCommand.ExecuteReader()来读取数据。然后我循环遍历队列并为每一行分别执行INSERT语句。我想象的是,不是逐行插入,而是做某种(可能是Linq语句)。有没有人有任何想法如何更快地插入我的插入?
队列定义:
private static readonly BlockingCollection<HistorianData> ValueQueue = new BlockingCollection<HistorianData>(new ConcurrentQueue<HistorianData>(), 1000000);
阅读:
public static void EnqueueHistorianData(SqlConnection connection, int idToAdd, DateTime minDatetime, DateTime maxDateTime, string cluster, string dbName, string dataTable, string idTable, string mainIdColumn, string foreignIdColumn, string dateColumn, string nameColumn, string valueColumn)
{
StringBuilder select = new StringBuilder();
HistorianData values;
select.Append(String.Format("SELECT {0}.{1},", dataTable, dateColumn));
select.Append(String.Format(" '{0}.' + {1}.{2},", cluster, idTable, nameColumn));
select.Append(String.Format(" {0}.{1}", dataTable, valueColumn));
select.Append(String.Format(" FROM {0}.{1}", dbName, dataTable));
select.Append(String.Format(" JOIN {0}.{1}", dbName, idTable));
select.Append(String.Format(" ON {0}.{1} = {2}.{3}", dataTable, foreignIdColumn, idTable, mainIdColumn));
select.Append(String.Format(" INNER JOIN Runtime.dbo.Tag"));
select.Append(String.Format(" ON Runtime.dbo.Tag.TagName = '{0}.' + {1}.{2}", cluster, idTable, nameColumn));
select.Append(String.Format(" WHERE {0}.{1} >= '{2}'", dataTable, dateColumn, minDatetime.ToString()));
select.Append(String.Format(" AND {0}.{1} = {2}", dataTable, foreignIdColumn, idToAdd.ToString()));
select.Append(String.Format(" AND {0}.{1} >= '{2}'", dataTable, dateColumn, minDatetime.ToString()));
select.Append(String.Format(" AND {0}.{1} < '{2}'", dataTable, dateColumn, maxDateTime.ToString()));
using (var command = new SqlCommand(select.ToString(), connection))
{
command.CommandTimeout = 1000;
using (var reader = command.ExecuteReader())
{
if (reader.HasRows)
{
while (reader.Read())
{
values = new HistorianData();
values.SampleDate = reader.GetDateTime(0);
values.TagName = reader.GetString(1);
values.TagValue = reader.GetDouble(2);
ValueQueue.Add(values);
}
values = null;
reader.Close();
}
}
}
}
写作:
public static void WriteQueueValuesToHistorian(string connectionString)
{
HistorianData values;
using (var connection = new SqlConnection(connectionString))
{
connection.Open();
using (SqlCommand insertCommand = connection.CreateCommand())
{
insertCommand.CommandType = CommandType.Text;
insertCommand.CommandText = "INSERT INTO Runtime.dbo.History (DateTime, TagName, Value, QualityDetail) VALUES (@P1, @P2, @P3, 192)";
insertCommand.CommandTimeout = 1000;
var param1 = new SqlParameter("@P1", SqlDbType.DateTime);
insertCommand.Parameters.Add(param1);
var param2 = new SqlParameter("@P2", SqlDbType.NVarChar, 512);
insertCommand.Parameters.Add(param2);
var param3 = new SqlParameter("@P3", SqlDbType.Float);
insertCommand.Parameters.Add(param3);
insertCommand.Prepare();
while (!ValueQueue.IsCompleted && ValueQueue.TryTake(out values, System.Threading.Timeout.Infinite))
{
int retries = 0;
while (retries < 3)
{
insertCommand.Parameters["@P1"].Value = values.SampleDate.ToLocalTime();
insertCommand.Parameters["@P2"].Value = values.TagName;
insertCommand.Parameters["@P3"].Value = values.TagValue;
try
{
insertCommand.ExecuteNonQuery();
retries = 4;
}
catch (SqlException)
{
retries += 1;
sw.WriteLine("SQLException - Values: " + insertCommand.Parameters["@P1"].Value + ", " + insertCommand.Parameters["@P2"].Value + ", " + insertCommand.Parameters["@P3"].Value);
}
}
}
}
}
}
的[SqlBulkCopy的](http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlbulkcopy(V = vs.110)的.aspx)类确实具有优化从读取内置的SqlDataReader中读取。而不是将记录读取到并发队列中,然后将它们写回来,是否可以在第一个函数的'reader'上使用SqlBulkCopy? – 2014-10-27 15:10:26
我试着走这条路。我的目标数据库实际上是专有的,并通过使用定制OLEDB接口的链接服务器进行引用。批量插入不适用于链接的服务器。 – clintperry 2014-10-27 16:10:07
连接字符串是否都转到同一个SQL服务器上用于这两种功能(链接服务器是否与源数据库在同一台服务器上链接)?如果是这样,为什么你完全通过C#,为什么不直接在单个查询中查询呢? – 2014-10-27 16:26:19