db2日志管理（完成）
---归档日志db2 update db cfg for dbtest using logretain recovery userexit ondb2 update db cfg for dbtest using logarchmeth1 DISK:D:/DB2/Arch_logdb2 update db cfg for dbtest using logarchmeth2 DISK:D:/DB2/Arch_log2db2 update db cfg for dbtest using LO
