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ORA-01190或1189的处理过程
SQL> startupORACLE 例程已经启动。Total System Global Area 838860800 bytesFixed Size ...
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How to identify a session started by a remote distributed transaction
select username, osuser, status, sid, serial#, machine, process, terminal, programfrom v$sessionwhere saddr in (select k2gtdses from sys.x$k2gte );
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where temp segment of temp table are created
Temporary segmentTemporary segments are created by Oracle when a SQL statement needs a temporary database area to complete execution. When the statement finishes execution, the extents in the tem...
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Force dynamic sampling for Global Temporary Tables
上线前业务测试过程中，需要找出低效以及潜在的抵消语句，发现有一个语句是个潜伏的定时炸弹：select distinct CATA_ID from PD_CATA_DICT where eff_date<sysdate and exp_date>sysdate start With CATA_ID in (se...
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正在执行的cursor无法从share pool中purge
今天应用测试的时候发现一个语句执行很慢，通过session找出sql_Id，看了下执行计划，一个小表对一个大表做nl关联，而且大表是全表扫描，不用问，执行计划的问题，于是查看对象是否做表分析，发现表分析20刚做过，通...
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关于alter table modify cloumn需要注意的
alter table add columnalter table drop columnalter table modify column三种操作是有区别的，其中 alter table add columnalter table drop column两种操作不会涉及对源表的dml操作，modify可能会产生源表...
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Oracle Senior DBA Wanted
Description:The Oracle DBA is a member of a top DBA Team responsible for eBay global Oracle database system. Responsibilities:· Work with different team member to deploy ebay application with proper...
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相关truncate/drop table的bug
bug 3282805: TRUNCATE TABLE SCANS FOR SMALL TABLES ENTIRE BUFFERCACHE数据库版本9.2.0.4PROBLEM:--------Truncate table takes on system with large buffercaches to long. It scans the complete cache to f...
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Range Partitioning 中VALUES LESS THAN 算法
dsi 302 lession 8The VALUES LESS THAN clause applies to all of the partitioning columns collectively. Therefore, the value in the partition key’s first column can be equal to the first column of the...
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10g synonym也可以invalid
10g之前，同义词从来不会invalid，因为没有依赖关系，10g中synonym和base之间有了依赖关系，具体可以查看视图DBA_DEPENDENCIES;导致synonym失效的原因见如下几种：This can happen for many reasons. Some of them...
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assm不仅可以减少buffer busy wait等待还可以减少itl等待
对于assm可以减少buffer busy wait中的freelist断头块争用很多文章都有提到过，今天做了个实验，对于insert操作也可以分离块的选择，对于不同的session选择不同的块进行insert，test如下create table zz（id char（...
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oracle中的userenv及sys_context的参数
1、 USERENV(OPTION) 返回当前的会话信息. OPTION='ISDBA'若当前是DBA角色,则为TRUE,否则FALSE. OPTION='LANGUAGE'返回数据库的字符集. OPTION='SESSIONID'为当前会话标识符. OPTION='ENTRYID'返回可...
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system dump-----------Library Object Lock State Object
Example: LIBRARY OBJECT LOCK: lock=30a6d48 handle=323fe98 mode=X call pin=0 session pin=0 user=302714c session=302714c count=1 flags=[00] savepoint=86 LIBRARY OBJECT HANDLE: ha...
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system dump------------Enqueue State Object
Example: (enqueue) MR-00000008-00000000 [O8: DID: <instance number>-<Oracle PID>-<sequence number> ] lv: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 res:304c7fc, mode: S, prv: 304c804, sess: 3024...
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gc cr request 'gcs log flush sync'
This is how it happens -1)You fired an update statement on Instance-2. 2)However, the request for desired blocks was gone to Instance-1. So Instance-2 was waiting on ''gc cr request'. 3)Instance-1 had...
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bind peeking
Create Table PreferredMeals (EmpID Number(5), Meal Varchar2(10) ) / Begin For i in 1..74998 Loop Insert Into PreferredMeals Values (i, 'Mansaf'); End Loop; Insert Into PreferredMeals Values (74999, '...
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invalidate the plans in shared pool
To invalidate any cursor, one of the followings can be done:1. Issue the command Alter System Flush Shared_Pool; 2. Delete or change the cursor underlying objects statistics 3. Grant...
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table 和index的parallel
在建表和索引的过程中，可以指定parallel参数来加快速度，但是很多人使用之后忘记将他们改回去，导致sql的效率低下，为了找出库中这些表和索引，我们可以使用以下语句select degree,count(*) from dba_indexes grou...
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rac 裸设备owner不一致导致的数据库hang
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批量create table出现的等待
上线过程中由于应用的需要，将大量分区非常多的分区表分成单表，于是需要批量create table，起了100个进程同时并发create table，过程中出现了大量的enq: TX - row lock contentionrow cache lockenq: TX - alloc...
