数据去哪了?现实版 (partition data invalid)

前几天有业务部门反应有个表的数据带上条件查询不出来,不带数据则可以,表没有做特殊处理,11.2.0.3 RAC on Exadata,后来找到了问题的原因,和圈里朋友Toms_zhang谈起此事, weibo圈子影响力就是大,张天师发weibo后引起不小风波,崔华和杨廷坤等大师也纷纷参于讨论, 今晚值班无事在这里把这个事件的源头生产库现实版分享一下。 SQL> select cycle,CODE from ANBOB.T_HIST where cycle=201507 and rownum<10; CYCLE     CODE ———- ———- 201507        310 201507        310 201507        310 201507        310 201507        310 201507        310 201507        310 201507        310 201507        310 9 rows selected. SQL> select cycle,CODE from ANBOB.T_HIST where cycle=201507 and rownum<10 and CODE=310; no rows selected SQL> … Read more

Oracle Database History

In 1977 Larry Ellison saw a IBM Journal of Research and Development, discovered a research paper that described a working prototype for a relational database management system (RDBMS). Showing it to coworkers Bob Miner and Ed Oates at Ampex .

Tuning: latch: cache buffers chains 又一案例

CBC latch竞争的原因很多,通常也可以理解为一种热块, 对于CBC 通常都是从session wait中找到child latch address 然后再去x$bh的hladdr字段找到相应的obj,1个BH handle可以会关连多个obj, 再参考TCH 列确认比较hot的对象。大多数CBC的OLTP系统多数应该注意一下sql 的执行计划中使用了NL join的方式;

Troubleshooting the crsd.bin and listener process terminal after eanble TCP.VALIDNODE_CHECKING in sqlnet.ora

Recently, we met several times Oracle Listener terminal case, here I will be sharing again due to configuration Listener whitelist caused, For to system hardening, we are eanble listener whitelist (TCP.VALIDNODE_CHECKING = yes) on some RAC Environment, But no more after prolonged listening terminated unexpectedly after enable VALIDNODE_CHECKING . [oracle@anbob2:/home/oracle]# ps -ef|grep lsnr oracle 5111994 … Read more