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节前有个网友向我咨询他们的生产库遇到了ora-8103,错误的block 是 SEGMENT HEADER BLOCK, 不可以简单通过rowid 跳过， 也不能像修改data block corruption 那样通过bbed 修改块为 corrupted 然后通过 dbms_repair.skip_corrupt_blocks 跳过该块， 该segment header block上都没有extent 信息(如extent map\HWM)…
A friend from QQ Group find me, he removed a online datafile from the his production database, but for as long as the database remains up. he re I take a demo to show recovery process. …
有时oracle 实例异常终止，会导致oracle process killed,但是实例之前所分配的shared memory segments没有release, 而此时登录提示no login，而且本机还有其它实例在用无法kill 所有…
Today I to read a SR, saw a case , to face a ora-7445 internal error when open resetlogs database after do database recovery. So here I collected some ora-7445 [unable_to_trans_pc] [UNABLE_TO_READ] errors with frequently ways to Troubleshooting .
Oracle 12.1.0.2 发布引入了一系列的新特性，当然还有关注度非常高的ORACLE In-Memory Option,在内存中提供一种列级的存储， 在OLTP中提供更好的性能，当然在Exadata中ORACLE已在存储级提供了列级的性能优化hybrid columnar compressed (HCC) format…
12c引入的可插拔的数据库容器(Multitenant Database)框架，在CDB中容器中的有1个或多个(Pluggable Databases)PDB，同时有一些参数是可以在PDB级别修改， 我们暂时称为PDB local parameter, PDB 级的参数对于PDB自身影响会覆盖(优先)从CDB继承的参数…
The Oracle Database is crashing down in few minutes as soon as we start the Database. DB 11.2.0.4 in linux single instance . it is in VMWare 6, Done a dynamic disk allocation before the problem occurred . then check alert log found ORA-600 [kdBlkCheckError] and ORA-600[4194] errors.
Why is my database after running for some time , large number of database server processes will be created , but the number of sessions is very little, what actions cause orphaned processes? And sometimes hit ora-20 error..
很久前在国外的一个blog就看到说是oracle RDBMS(not NOSQL)要支持JSON, 当时说是XMLDB 开发组在做这个事情，随着oracle 12.1.0.2 release 得到确认，的确引入这一特性，JSON, JavaScript Ojbect Notation 在结构上和XML有很多相似之处, 而且这种Schema less data management的数据模型在NOSQL 中广泛应用，数据的存储相对更加紧凑，避免有时空列致ORACLE RDBMS中表一些数据”洞”…
ora-600 [kdsgrp1] 发生fetch 操作查找预期的行失败时, 常有ora-600 [qertbFetchByRowID] 伴随，这次遇到的一个aix 10.2.0.4 rac案例有 ora-7445 [kdr9ir2F0rst4srp0+0068] 和 ora-600 [25027], [6], [825242163] 陪伴, 而且 ora-600 [25027] 的rdba 莫名指向了一些不相干数据块..
ORA-39095 : ” dump file space has been exhausted. Unable to allocate 8192 bytes”
HOW do I fix the ORA-39095 error?
Answer:
There are several likely reasons for this error:…
The ORA-600 [KKMUPSVIEWDESTFRO_4] happens while running a merge statement with join elimination. Such join elimination can only happen if the fix for bug 7679164 is present and enabled. This fix was included in the 11.2.0.1 base release.
By default DBUA removes all the hidden parameters during upgrade.If you want to keep the hidden parametersinvoke DBUA with ‘keepHiddenParams’ option.e.g./dbua -keepHiddenParams
有一个procedure中一段SQL用到了synynom,而synonym指向一个dblink所对应的表，其中是两个子查询做了full join,在procedure 编译时提示ORA-00942: table or view does not exist，而把那段plsql 查询语句块拿出来，做为单条SQL执行时完全正常且有返回结果…
If you are grant privilege to new account like this “grant connect, resource to username”, as you know from 11g the role “Connect” only have “create session” privilege , but now in 12c ,the role “Resource” privilege had changed too.
接上一篇 http://www.anbob.com/archives/2323.html 下面我们从统计信息入手 sys@DEVDB>select count(distinct join_course_count),count(distinct is_course_qual),count(*) from app_zyyjhj.em_examinee; COUNT(DISTINCTJOIN_COURSE_COUNT) COUNT(DISTINCTIS_COURSE_QUAL) COUNT(*) ——————————– —————————– ——————– 6 4 35765 #使用tabstat2 脚本收信表信息，我已截断输出 sys@DEVDB>@tabstat2 em_examinee app_zyyjhj Table Number Empty Average Chain Average Global User Sample Date Name of Rows Blocks Blocks Space Count Row Len Stats Stats Size MM-DD-YYYY ————— ————– ——– ———— ——- ——– ——- —— —— … Read more
当CBO产生的Cardinality过低，尤其是在表之间关连时，往往会差之毫厘差之千里，甚至影响表之间的join方式，注意下MERGE JOIN CARTESIAN部分，这里使用了一种NL style的MJ,..
注意上面的4# 计划 的fileter 部分， 这就是问题的根源。了解SQL的执行步骤应该清楚在sql parse阶段CBO会帮我们做sql查询转换生成高效的执行计划, 在本案例我们想把TO_NUMBER(“S”.”SCORE”)<60 的条件放到子查询返回的结果集后再过滤, 结果CBO错误把此条件提前和该字段的其它条件一并执行..
RMAN Tablespace Point-In-Time Recovery ( TSPITR) enables you to quickly recover one or more tablespaces in an Oracle database to an earlier time, without affecting the state of the rest of the tablespaces and other objects in the database.
DBPITR enables you to recover a database to some time in the past.I will demonstrate below how to do flashback a database to a point in time.