Question

我在MS-Sqlserver 2008上使用存储过程，它生成一个渐进的字母数字序列，用于在另一个表中存储不同数据的负载。

但是现在，当多个进程几乎同时访问此存储过程时，通常会出现问题。

有没有人有建议，如何建立或如何解决这些问题？

以下是SP的实际代码：

CREATE PROCEDURE [dbo].[GetNextAlpha] @s varchar(8) OUTPUT
AS
BEGIN TRANSACTION
DECLARE @res INT;
EXEC @res = sp_getapplock
            @Resource = 'Upsert_app_lock',
            @LockMode = 'Exclusive',
            @LockOwner = 'Transaction',
            @LockTimeout = 2000,
            @DbPrincipal = 'public';

IF @res NOT IN (0, 1)
BEGIN
    RAISERROR ( 'Unable to acquire Lock', 16, 1 )
END
ELSE
BEGIN

    DECLARE @n CHAR(36) = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
    DECLARE @pos TINYINT;

    SET @s = (SELECT TOP 1 [CurHighKey] FROM [dbo].[HighKey]);
    SET @pos = LEN(@s);

    WHILE @pos > 0
    BEGIN
        IF SUBSTRING(@s, @pos, 1) = 'Z'
        BEGIN
            SET @s = STUFF(@s, @pos, 1, '0');
            SET @pos = @pos - 1;
        END
        ELSE
        BEGIN
            SET @s = STUFF(@s, @pos, 1, SUBSTRING(@n, CHARINDEX(SUBSTRING(@s, @pos, 1), @n) + 1, 1))
            SET @pos = 0
        END
    END

    UPDATE [dbo].[HighKey] set [CurHighKey] = @s;

    EXEC @res = sp_releaseapplock
                @Resource = 'Upsert_app_lock',
                @DbPrincipal = 'public',
                @LockOwner = 'Transaction';

END

COMMIT

字母数字序列的存储过程导致重复键

0 个答案: