Oracle 哪些进程可以KILL不会导致实例重启？
oracle后台进程当出现问题时，有些进程kill会导致实例立即重启，像smon, pmon,ckpt.. , 而有些进程kill并不会影响实例可用性， 甚至会立即做进程级重启从db alert log可以观测到，如mmon,rec,jnnn, pnnn等，...
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Troubleshooting ORA-01578 ORA-01110 ORA-26040 NOLOGGING corrupted block
The following errors have recently occurred in our database( Oracle 19c RAC): ORA-01578: ORACLE data block corrupted (file # xxx, block # yyyyy) ORA-01110: data file xxx: 'xxxxxxxxxxxxxxxxx.dbf'...
View ArticleOracle 12c Alert log show ” ADVISORY: Please collect redo for investigation...
叕一个oracle 12c频繁生成日志文件的问题，最近一套12.2的RAC突然又文件系统告警，生成了大量的trace文件，db alert log也在不停的显示如下内容。该表分区较多，前一晚有做该表move操作。 # alert log ADVISORY: Please collect redo for investigation of ORA-8103. Use command: ALTER...
View ArticleEnable DDL logging in Oracle databaase (安全审计)
Oracle database use DDL statements to define structures such as tables to store data and functions to store code. Monitoring, auditing and logging changes to DDL are key components of a database...
View ArticleTroubleshooting ORA-00600 [ORA_NPI_ERROR] ORA-00600: internal error code...
Oracle 11.2.0.3 2nodes RAC on AIX, node1 DB instance crash and db alert log show “ORA-00600 [ORA_NPI_ERROR] ORA-00600: internal error code [kffilCreate01]” and “ORA-15064: communication failure with...
View ArticleWait Event: Wait for Table Lock
Wait for Table Lock Meaning: Wait for exclusive TM enqueue in materialized view operations. Optimization steps: In the SAP environment, materialized views (Note 741478) are only implicitly used as...
View ArticleAlert: Remember to specify the table name alias for column of the subquery...
前几日同事那遇到的灾难性的SQL, 一个简单的子查询，不知是一开始就写错了子查询中的列名，还是子查询的表后期有改列名，导致主查询表所有数据被更改，在未指定列所属表名时，列的查询顺序先检查子查询再检查主查询，这是oracle的预期行为，并不会报列不存在，只是在后期书写时子查询记的增加列上的所属别名。 -DEMO SQL> @st anbob.tp ID NAME ----------...
View ArticleOracle 20c新特性: dbms_xplan.display_awr 增加了谓词信息
执行计划中的谓词信息非常的重要，有助于我们判断是否进行了隐式转换，为什么没有使用索引等， 使用dbms_xplan.display_cursor可以从shared_pool中取到sq cursor的谓词，但是在20c之前dbms_xplan.display_AWR 在之前的版本中并不能， 但是在Oracle社区的投票和诸多人的推动下，终于在oracle...
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DB Time 去哪了？ Oracle 12C AWR 增加了on cpu runqueue
是否遇到过在分析AWR报告时，明明AAS很高，但从Top 10 Foreground Events by Total Wait Time 上看top event使用的百分比加起来离100%很远？ 那DB TIME去哪了？下面我附一个11G(11.2.0.4 RAC on AIX) AWR 案例，这个问题在12c的AWR中提供了TOP EVENT。 Host Name Platform CPUs...
View ArticleOracle数据库许可(License)
Oracle产品可从Oracle网站免费下载。但是，在使用它之前，您需要同意Oracle Technology Network（OTN）开发人员许可条款。最近几年虚拟化、云化环境的普及，Oracle的license许可有些疑惑，在这里特意整理一下。Oracle文档中关于此主题的信息确实很少，稍不注意可能会带了百万级的费用消耗,...
View ArticleBBED simulates and fixes ORA-08102 error (Oracle 19c)
Sometimes due to sudden power failure and other reasons, the database data dictionary is inconsistent, such as hits ora-8102, the indexes key and the table key value does not match, often delete the...
View ArticleBBED simulates and fixes ORA-08102 error (Oracle 19c) (二)
BBED simulates and fixes ORA-08102 error (Oracle 19c) 方法一使用了bbed修改 index key的方法， 因为表列上只有这一个索引，所以只改一个索引就可以。这里还使用相同的方法模拟ora-8102,使用第二种方法，删除bootstrap$中的index I_OBJ4 记录解决。 SQL> show pdbs CON_ID CON_NAME...
View ArticleWait event: enq: HW – contention
这是一套11G数据库，一线DBA反应是数据库活动会话很高， 要来一份AWR，显示数据库top event中较高的是enq: HW – contention和enq: TX – row lock contention，而另一节点是有较高的direct path read. DB Name DB Id Instance Inst num Startup Time Release RAC ANBOB...
View ArticleTroubleshooting ORA-27102: out of memory Linux-x86_64 Error: 12: Cannot...
Insufficent memory related errors (i.e: ORA-27xxx).ORA-27102 error may occur because of insufficient shared memory segments. ORA-27102 on Startup A] Ensure that the physical RAM is greater than the...
View ArticleOracle 11g 12c 18c 19c .. IMPDP Always Creates Indexes with Degree 1
Indexes seem always created with parallel degree 1 during import as seen from a sqlfile. Even if the specified parallelism is greater than 1. like 1, Version 11.1.0.7 11.2.0.1 # impdp .......
View ArticleOracle 12c 19c Automatic terminal/kill session feature
数据库会话同样会占用数据库资源，如客户端异常断开在客户端成为一个dead session会永远存在，如果客户端没有断开也没有活动就是一个idle session， 如果这个idle session做了一些修改未提交，然后下班或去吃饭、上WC、开会等，这时就会堵塞其他人对相同的数据做修改，这类会话可以叫做idle blocker session. 在自治数据库的时代这些session...
View Article升级Oracle 19c经验: TTS 在使用datapump导matadata时EXCLUDE=STATISTICS 不启作用
在使用TTS迁移一个8T 的11.2.04到19c PDB时，发现expdp和imdp元数据过程中statistic占用了约1个多小时的时间， 但是我检查了实时步骤中确实有写exclude=statistics，猜测是参数没启作用，不能忍，需要确认下原因。 结果发现这是一个预期行为，因为在TTS metadata时statistics不是exclude的有效值。 这样即使在expdp...
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Oracle Internal BLOCK CHANGE TRACKING
Oracle RMAN was able to take incremental backups already in 9i. However, prior to introduction of Oracle 10g block change tracking (BCT), RMAN had to scan the whole datafile to and filter out the...
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How to disable DRM? Oracle 10G, 11G, 12C-19C
DRM is driven by the following 1.) _gc_affinity_time = Time in minutes at which statistics will be evaluated (default = 10 mins) 2.) _gc_affinity_limit = # of times a node accesses a file/object...
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