如何最大限度地减少\提前计划运行 sp_delete_backuphistory 的影响？也衡量收益！

Question

运行以下查询时：

-- DATEADD (datepart , number , date )  

DECLARE @dt DATETIME
SELECT @dt = DATEADD(month,-6,getdate())
select @dt
EXEC msdb.dbo.sp_delete_backuphistory @oldest_date = @dt 

我收到很多锁和块，可能是因为该命令已经有一段时间没有运行了（如果有的话）。

在我实际运行或计划运行此命令之前，有没有办法找出每个涉及的表中有多少要删除的内容？

我使用dateadd来计算 6 个月。

在sp_delete_backuphistory中，以下表被修剪：

sp_delete_backuphistory 必须从 msdb 数据库运行并影响以下表：

备份文件

备份文件组

备份媒体家族

备份媒体集

备份集

恢复文件

恢复文件组

恢复历史

Answer 1

我对这个过程的抱怨可以追溯到很久以前：

• 糟糕的代码年鉴，第 1 部分：批评代码
• 糟糕的代码编年史，第 2 部分

删除大量数据时遇到的问题是从表变量中获得的蹩脚估计。

我很幸运地使用临时表创建了新版本的过程。您也可以尝试仅添加重新编译提示，但是嘿，这样我们就可以获得有用的索引。

附带说明：如果由于运行时间较长而仍然遇到此阻塞，您可以尝试删除事务代码，或更改它以封装每个单独的删除（尽管此时的好处可以忽略不计）。

CREATE   PROCEDURE [dbo].[sp_delete_backuphistory_pro]
   @oldest_date datetime
 AS
 BEGIN
   SET NOCOUNT ON

   CREATE TABLE #backup_set_id      (backup_set_id INT PRIMARY KEY CLUSTERED)
   CREATE TABLE #media_set_id       (media_set_id INT PRIMARY KEY CLUSTERED)
   CREATE TABLE #restore_history_id (restore_history_id INT PRIMARY KEY CLUSTERED)

   INSERT INTO #backup_set_id WITH (TABLOCKX) (backup_set_id)
   SELECT DISTINCT backup_set_id
   FROM msdb.dbo.backupset
   WHERE backup_finish_date < @oldest_date

   INSERT INTO #media_set_id WITH (TABLOCKX) (media_set_id)
   SELECT DISTINCT media_set_id
   FROM msdb.dbo.backupset
   WHERE backup_finish_date < @oldest_date

   INSERT INTO #restore_history_id WITH (TABLOCKX) (restore_history_id)
   SELECT DISTINCT restore_history_id
   FROM msdb.dbo.restorehistory
   WHERE backup_set_id IN (SELECT backup_set_id
                           FROM   #backup_set_id)

   BEGIN TRANSACTION

   DELETE FROM msdb.dbo.backupfile
   WHERE backup_set_id IN (SELECT backup_set_id
                           FROM   #backup_set_id)
   IF (@@error > 0)
     GOTO Quit

   DELETE FROM msdb.dbo.backupfilegroup
   WHERE backup_set_id IN (SELECT backup_set_id
                           FROM   #backup_set_id)
   IF (@@error > 0)
     GOTO Quit

   DELETE FROM msdb.dbo.restorefile
   WHERE restore_history_id IN (SELECT restore_history_id
                                FROM   #restore_history_id)
   IF (@@error > 0)
     GOTO Quit

   DELETE FROM msdb.dbo.restorefilegroup
   WHERE restore_history_id IN (SELECT restore_history_id
                                FROM   #restore_history_id)
   IF (@@error > 0)
     GOTO Quit

   DELETE FROM msdb.dbo.restorehistory
   WHERE restore_history_id IN (SELECT restore_history_id
                                FROM   #restore_history_id)
   IF (@@error > 0)
     GOTO Quit

   DELETE FROM msdb.dbo.backupset
   WHERE backup_set_id IN (SELECT backup_set_id
                           FROM   #backup_set_id)
   IF (@@error > 0)
     GOTO Quit

   DELETE msdb.dbo.backupmediafamily
   FROM msdb.dbo.backupmediafamily bmf
   WHERE bmf.media_set_id IN (SELECT media_set_id
                              FROM   #media_set_id)
     AND ((SELECT COUNT(*)
           FROM msdb.dbo.backupset
           WHERE media_set_id = bmf.media_set_id) = 0)
   IF (@@error > 0)
     GOTO Quit

   DELETE msdb.dbo.backupmediaset
   FROM msdb.dbo.backupmediaset bms
   WHERE bms.media_set_id IN (SELECT media_set_id
                              FROM   #media_set_id)
     AND ((SELECT COUNT(*)
           FROM msdb.dbo.backupset
           WHERE media_set_id = bms.media_set_id) = 0)
   IF (@@error > 0)
     GOTO Quit

   COMMIT TRANSACTION
   RETURN

 Quit:
   ROLLBACK TRANSACTION

 END