如果SQL SERVER 日志过大，比如，达到了几十个G，想一次性收缩的，直接执行下面命令即可：
USE DATABASENAME;
GO
– Truncate the log by changing the database recovery model to SIMPLE.
ALTER DATABASE DATABASENAME
SET RECOVERY SIMPLE;
GO
– Shrink the truncated log file to 1 MB.
DBCC SHRINKFILE (DATABASENAME_Log, 1);
GO
– Reset the database recovery model.
ALTER DATABASE DATABASENAME
SET RECOVERY FULL;
GO
正常来讲，应该是先执行一次备份事务日志，然后在执行数据库收缩命令，就能正常的收缩日志大小了。
1、定时执行备份事务日志，每天凌晨1点执行
BACKUP LOG [uiyi] TO DISK = N’F:DB_BackupLoguiyiuiyi_backup_2013_06_21_145209_5008471.trn’ WITH NOFORMAT, NOINIT, NAME = N’uiyi_backup_2013_06_21_145209_4948467′, SKIP, REWIND, NOUNLOAD, STATS = 10
2、收缩日志，每天凌晨2点执行
use uiyi
go
DBCC SHRINKFILE (uiyi1224_Log, 50);
3、备份全量数据库，每天凌晨3点执行
BACKUP DATABASE [uiyi] TO DISK = N’F:DB_BackupAlluiyiuiyi_backup_2013_06_21_145557_3298781.bak’ WITH NOFORMAT, NOINIT, NAME = N’uiyi_backup_2013_06_21_145557_3268780′, SKIP, REWIND, NOUNLOAD, STATS = 10
GO