The lowercase and quotes table names may not be able to audit(小写表名可能不会审计)

昨一好朋友问我开了审计,有些表但无审计记录。 下面我来还原这个问题 db_version oracle 10201 for linux SQL> show parameter audit NAME TYPE VALUE ———————————— ———– —————————— audit_file_dest string /u1/oracle/admin/ORCL/adump audit_sys_operations boolean FALSE audit_syslog_level string audit_trail string DB, EXTENDED audit select any table by access; SQL> select os_username,username,terminal,timestamp,owner,obj_name,audit_option from DBA_AUDIT_TRAIL order by 4; OS_USERNAM USERNAME TERMINAL TIMESTAMP OWNER OBJ_NAME AUDIT_OPTION ———- ———- ———- ——————- —————————— … Read more

ORA-1688: unable to extend table SYS.WRH$_ACTIVE_SESSION_HISTORY

1) Export the snapshots and then do a manual purge To purge the Table SYS.WRH$_ACTIVE_SESSION_HISTORY, you may first query the Snapshot History with the query below: select snap_id, begin_interval_time from sys.dba_hist_snapshot order by snap_id; Then, you choose the range of snapshot you want to delete, and you execute the following Procedure: exec dbms_workload_repository.drop_snapshot_range ( low_snap_id … Read more

How to config hugepage on Linux for Oracle(配置大页)

内存管理是一个非常复杂的结构,在操作系统中用Virtual memory System进行内存管理,pagetable是中记录了内存的虚拟地址和物理地址的映射关系,当一个进程真正的访问数据是首先访问的是page table然后转向真实的地址,cpu中有固定的大小来缓存部份的pagetables,这块区域就是translation lookaside buffer(TLB).

about get bind_data column in v$sql(绑定变量值)

今天查看AWR时,发现有个sql占用的cpu很高而且也并不复杂,top 5 event出现了cpu,read by other sessions,而且sql中再次看到的hint index,随后从生产环境中拿到绑定变量参数值进行本地调试,发现hint index 选择了错误的索引一致读为93万,去掉hint立即降低到了36,随后服务器压力将了下来

Session-Level init Parameters or Environment(会话级参数环境)

sometimes we use ALTER SESSION statement to set or modify any of the conditions or parameters that affect your connection to the database. The statement stays in effect until you disconnect from the database. we can query current system Initialization parameter from v$parameter view,but where are able to confirm that the session-level parameter modification happened?

Invisible Indexes in oracle11g

11gr1起提供了Invisible Indexes,作用就是通过alter index xx invisible,对CBO隐身,我突然想到之前的一个情况,就是开发的在应用中滥用hint index,当时为了让hint index 无效,当时是选择index rename,现在看来如果是11g可以用invisible