Block split and entry reorder

December 12, 2012 Internals, oracle No comments

今天跟研发的同学讨论到了这个问题,index block split过程中涉及到的重新排序问题.

SQL> create table idx_split (a number, b varchar2(1446), c date);   
Table created


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August 17, 2012 Internals, maintain, oracle 2 comments

帮朋友check一次中国银联数据库的坏块问题(并不是严格意义上的坏块),大致情况为smon需要trascation recover —>特定的block 发现无法读取 —>transaction recover出现问题 —>smon terminated

Wed Aug 15 19:02[……]

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Bitmap index tips

June 7, 2012 Internals, oracle No comments

对于BITMAP index的使用 一直存在一些争议 我们来看看下面几个观点:

1. Low cardinality – Some dabase vendor, like Oracle, provides very practical suggestion

If the num[……]

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March 8, 2012 Internals, maintain, oracle 1 comment

昨天看了roger的一篇文章,如何在创建index 之前估算它的大小,这里有一种更简单的方法实现:


–create a testing table named t
SQL> create tabl[……]

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Fractured blocks when Rman backup is running

February 20, 2012 backup, oracle, replication No comments

系统alert在主库出现下面错误 OS为linux 5.5

Stopping background process CJQ0
Sat Feb 11 03:41:07 2012
Hex dump of (file 9, block 561424) in trace file /data/[……]

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HugePages on Linux

January 16, 2012 linux, system 5 comments

Regular Pages and HugePages

This section aims to give a general picture about memory access in virtual memory systems and how pages are referenced.[……]

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How does “Nologging” attribute

January 13, 2012 Internals, oracle No comments

NOLOGGING is supported in only a subset of the locations that support LOGGING. Only the following operations support the NOLOGGING mode:
1. Dir[……]

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Oracle 坏块处理(final)

January 8, 2012 maintain, oracle 2 comments


Hex dump of (file 7, block 1407500) in trace file /data/oracle/admin/orcl/bdump/orcl_p004_7383.trc
Corrupt block relativ[……]

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分区表中的index 失效及处理

January 4, 2012 maintain, oracle No comments

分区表中 local 索引的维护会在oracle 操作表分区的时候自动进行,需要注意的是global 索引,当global索引所在表执行alter table 涉及下列操作时,会导至该索引失效,需要重新建立:


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December 29, 2011 maintain, oracle 1 comment


— Create table
create table yhd_so_temp
(id NUMBER(18) not null,

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