为什么 SQL 服务器插入这么慢? [英] Why are SQL server inserts so slow?

问题描述

我正在尝试将内存数据行插入 SQL Server Express 2005 上的表中.它的运行速度在我看来非常缓慢 - 每插入 1000 行大约 5 秒.我只是使用基本的INSERT INTO"命令.缓慢与表数据无关 - 对于只有一个 int 列且没有索引的表，它仍然很慢.这与我的软件无关 - 它与 Management Studio 在循环中运行 SQL 的速度一样慢.没有其他东西同时访问数据库.在 3Ghz Xeon(我知道是旧的)上，这将需要大约 10 秒的时间来执行:

I'm trying to insert rows of in-memory data into a table on SQL Server Express 2005. It is running what seems to me very slowly - about 5 seconds per 1000 rows inserted. I am just using a basic "INSERT INTO" command. The slowness does not depend on the table data - it is still slow with a table with one int column and no index. It is nothing to do with my software - it is just as slow running SQL in a loop from Management Studio. There is nothing else accessing the database at the same time. On a 3Ghz Xeon (old I know), this will take about 10 seconds to execute:

declare @i int  
set @i = 0  
set nocount on  
while @i < 2000  
begin  
insert into testdb(testcolumn)  
values (1)  
set @i = @i + 1  
end  

有没有比 INSERT 循环更好的方法来插入大量内存数据?或者我应该在 SQL Server 中更改一些配置?

Is there a better way to insert bulk in-memory data than looping on INSERT? Or some configuration I should change in SQL Server?

推荐答案

您在自己的事务中执行每个插入.

You perform each insert inside its own transaction.

在SQL Server中开始和提交事务非常开销很大.

Beginning and committing transaction is very expensive in SQL Server.

将所有内容封装到一个事务块中:

Enclose everything into a single transaction block:

declare @i int
set @i = 0
set nocount on
BEGIN TRANSACTION
while @i < 2000
begin
insert into testdb(testcolumn)
values (1)
set @i = @i + 1
end
COMMIT

要生成示例数据，您可以使用递归CTE:

To generate sample data, you can use a recursive CTE:

WITH    q (num) AS
        (
        SELECT  1
        UNION ALL
        SELECT  num + 1
        FROM    q
        WHERE   num < 2000
        )
INSERT
INTO    testdb(testcolumn)
SELECT  1
FROM    q
OPTION (MAXRECURSION 0)

，这样会更快.

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