使用C＃在SQL Server上的临时表中插入3万行的最快方法

Question

我试图找出如何使用c＃在SQL
Server的临时表中提高插入性能的方法。有人说我应该使用SQLBulkCopy，但是我一定做错了，因为它看起来比仅仅构建一个SQL插入字符串要慢得多。

我使用SQLBulkCopy创建表的代码如下：

public void MakeTable(string tableName, List<string> ids, SqlConnection connection)
    {

        SqlCommand cmd = new SqlCommand("CREATE TABLE ##" + tableName + " (ID int)", connection);
        cmd.ExecuteNonQuery();

        DataTable localTempTable = new DataTable(tableName);

        DataColumn id = new DataColumn();
        id.DataType = System.Type.GetType("System.Int32");
        id.ColumnName = "ID";
        localTempTable.Columns.Add(id);

        foreach (var item in ids)
        {
             DataRow row = localTempTable.NewRow();
             row[0] = item;
             localTempTable.Rows.Add(row);
             localTempTable.AcceptChanges();
        }


        using (SqlBulkCopy bulkCopy = new SqlBulkCopy(connection))
        {
            bulkCopy.DestinationTableName = "##" + tableName;
            bulkCopy.WriteToServer(localTempTable);

        }
    }

这样，我的插入内容需要很长时间才能运行。我用其他方法使嵌件工作得更快：

我将插入位创建为字符串，并将其加入到我的SQL create temp table语句中：

创建插入字符串：

public string prepareInserts(string tableName, List<string> ids)
    {
        List<string> inserts = new List<string>();

        var total = ids.Select(p => p).Count();
        var size = 1000;

        var insert = 1;

        var skip = size * (insert - 1);

        var canPage = skip < total;

        while (canPage)
        {
            inserts.Add(" insert into ##" + tableName + @" (ID) values " + String.Join(",", ids.Select(p => string.Format("({0})", p))
                        .Skip(skip)
                        .Take(size)
                        .ToArray()));
            insert++;
            skip = size * (insert - 1);
            canPage = skip < total;
        }

        string joinedInserts = String.Join("\r\n", inserts.ToArray());

        return joinedInserts;

    }

创建查询后在SQL语句中使用它们：

inserts = prepareInserts(tableName, ids);

var query = @"IF EXISTS
                                            (
                                            SELECT *
                                            FROM tempdb.dbo.sysobjects
                                            WHERE ID = OBJECT_ID(N'tempdb..##" + tableName + @"')
                                            )
                                                BEGIN
                                                    DELETE FROM ##" + tableName + @"
                                                END
                                            ELSE
                                                BEGIN
                                                    CREATE TABLE ##" + tableName + @"
                                                    (ID int)
                                                END " + inserts;

            var command = new SqlCommand(query, sqlConnection);
...

Since I’ve seen people telling me (on stack exchange
https://dba.stackexchange.com/questions/44217/fastest-way-to- insert-30-thousand-rows-in-sql-server/44222?noredirect=1#comment78137_44222 )
That I should use SQLBulkCopy and that would be faster I believe that I should
improve the way I do it. So if anyone can suggest how I can improve my
SQLBulkCopy code OR tell me if there is a better insert statement that can
improve my application’s performance that would be great.

Answer 1

Your problem may be in localTempTable.AcceptChanges(); Since it commit your
changes.
If you do the next , I think it will run faster

    foreach (var item in ids)
    {
         DataRow row = localTempTable.NewRow();
         row[0] = item;
         localTempTable.Rows.Add(row);

    }

    localTempTable.AcceptChanges();

    using (SqlBulkCopy bulkCopy = new SqlBulkCopy(connection))
    {
        bulkCopy.DestinationTableName = "##" + tableName;
        bulkCopy.WriteToServer(localTempTable);

    }

From MSDN - DataSet.AcceptChanges

Commits all the changes made to this DataSet since it was loaded or since
the last time AcceptChanges was called.