sql-server - 限制 SQL Server 事务日志
问题描述
我目前有一个 SQL 脚本,它获取具有特定名称的所有表并从中删除记录。
这些表中有数百万条记录,因此即使恢复设置为 SIMPLE,事务日志也会不断增长。我将删除放在一个事务中,它一次只删除大约 50000 条记录。任何人都可以提出一些不让事务日志不受控制地增长的方法。下面是我正在运行的 SQL 的粗略示例。
DECLARE delete_cur CURSOR FOR
SELECT DISTINCT Name FROM Sys.tables WHERE name like 'ToDelete_%'
OPEN delete_cur
FETCH NEXT FROM delete_cur
INTO @tableName
WHILE @@FETCH_STATUS = 0 AND @timeToStop = 0
BEGIN
SELECT @RowCount = NULL, @MaxID = NULL, @MinID = NULL, @ID = NULL, @TableRowCount = 0
IF NOT Exists (Select 1 from ArchiveInfoAuditTables WHERE Name = @tableName)
BEGIN
SET @params = N'@MaxID_Out DECIMAL(18,0) OUT, @MinID_Out DECIMAL(18,0) OUT, @RowCount_Out DECIMAL(18,0) OUT';
SET @SQL = 'SELECT @RowCount_Out = COUNT(ID), @MaxID_Out = MAX(ID), @MinID_Out = MIN(ID) FROM ' + @tableName
print @SQL
EXEC sp_executesql @SQL, @params, @RowCount_Out = @RowCount OUT, @MaxID_Out = @MaxID OUT, @MinID_Out = @MinID OUT;
PRINT @tableName + ' Row Count: ' + CONVERT(VARCHAR, @RowCount) + ' Max ID: ' + CONVERT(VARCHAR, @MaxID) + ' Min ID: ' + CONVERT(VARCHAR, @MinID)
SET @params = N'@ID_Out DECIMAL(18,0) OUT, @Date DATETIME';
SET @SQL = 'SELECT TOP 1 @ID_Out = ID FROM ' + @tableName + ' WHERE AuditTimeStamp < @Date ORDER BY ID DESC'
print @SQL
EXEC sp_executesql @SQL, @params, @ID_Out = @ID OUT, @Date = @JanOfCurrentYear
INSERT INTO DeleteInfo (Name, StartDeletingFromID, MaxID, MinID, NumberOfRows)
VALUES (@tableName, @ID, @MaxID, @MinID, @RowCount)
END
ELSE
BEGIN
SELECT TOP 1 @ID = StartDeletingFromID FROM DeleteInfo WHERE Name = @tableName
END
IF (@ID IS NULL)
BEGIN
PRINT 'No Record needs to be deleted for Table: ' + @tableName
GOTO Fetch_Next
END
WHILE 1 = 1
BEGIN
BEGIN TRANSACTION
SET @params = N'@RowCount_Out DECIMAL(18,0) OUT, @NumOfRowsToDelete_Out BIGINT, @ID_Out DECIMAL(18,0)'
SET @SQL = 'DELETE TOP (@NumOfRowsToDelete_Out) FROM ' + @tableName + ' WHERE ID <= @ID_Out ;'
+ 'SELECT @RowCount_Out = @@RowCount'
PRINT @SQL
EXEC sp_executesql @SQL, @params, @RowCount_Out = @TempRowCount OUT, @NumOfRowsToDelete_Out = @NumOfRowsToDelete, @ID_Out = @ID
SET @TableRowCount += @TempRowCount
SET @TotalRowCount += @TableRowCount
COMMIT TRANSACTION
CHECKPOINT;
SET @MSG = 'Deleted ' + CAST(@TableRowCount AS VARCHAR) + '. ' + CONVERT(varchar, @TimeElapsed) + ' elapsed.'
RAISERROR (@MSG, 0, 1) WITH NOWAIT
IF @TempRowCount < @NumOfRowsToDelete BREAK;
END
Fetch_Next:
PRINT '/******************************************************************/'
FETCH NEXT FROM delete_cur
INTO @tableName
END
END_HERE:
CLOSE delete_cur;
DEALLOCATE delete_cur;
解决方案
您可以限制日志的大小(这里我们将大小限制为 512 MB):
ALTER DATABASE [DatabaseName] MODIFY FILE ( NAME = N'DATABASENAME_Log', SIZE = 512000KB , FILEGROWTH = 0)
为备份数据库创建维护作业并缩小日志
您可以使用这个简单的命令来缩小日志文件
DBCC SHRINKFILE (DataFile1, 512)
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