我有一个 ac# 应用程序,它从一个数据库中获取数据,进行必要的转换,并将数据插入另一个数据库的表中。我通过将源数据插入队列然后处理队列以将数据插入目标表来做到这一点。我有两个单独的线程来读取源数据和写入目标数据。读取线程的运行速度比写入线程快得多,因此我的队列很快就会填满。
正如您在阅读线程中看到的那样,我正在使用 SqlCommand.ExecuteReader() 来读取数据。然后我遍历队列并为每一行执行单独的 INSERT 语句。我所设想的是,不是逐行插入,而是做某种(可能是 Linq 语句)。有谁知道如何更快地插入我的插件?
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);
}
}
}
}
}
}