Oracle数据库块的物理损坏与逻辑损坏-创新互联

       
        笔者认为不能简单的说物理硬盘的损坏导致块的物理损坏，Oracle bug导致块的逻辑损坏。这篇文章我们来详细讨论一下Oracle数据库的物理损坏以及逻辑损坏的概念。下面是一篇METALINK的文章：

Physical and Logical Block Corruptions. All you wanted to know about it. [ID 840978.1]
		修改时间 21-MAY-2012     类型 BULLETIN     状态 PUBLISHED

In this Document

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Purpose

Scope

Details

Physical Block Corruptions

Fractured Block

Bad Checksum

Block Misplaced

Logical Block Corruptions

References

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Applies to:

Oracle Server - Enterprise Edition - Version 9.2.0.1 to 11.2.0.3 [Release 9.2 to 11.2]
Information in this document applies to any platform.
***Checked for relevance on 21-May-2012***

Purpose

Oracle classifies the Data File Block corruptions as Physical and Logical.  This is also referred as intra block corruptions.  This document is intended to provide detailed information and errors example about it.

Scope

This document is intended for Database Administrators.

Details

Physical Block Corruptions

This kind of block corruptions are normally reported by Oracle with error ORA-1578 and the detailed corruption description is printed in the alert log. 

Corruption Examples are:

• Bad header - the beginning of the block (cache header) is corrupt with invalid values
• The block is Fractured/Incomplete - header and footer of the block do not match
• The block checksum is invalid
• The block is misplaced
• Zeroed out blocks / ORA-8103

Detailed Corruption Description:

Fractured Block

A Fractured block means that the block is incomplete. Information from the block header does not match the block tail.

Corrupt block relative dba: 0x0380e573 (file 14, block 58739)
Fractured block found during buffer read
Data in bad block -
type: 6 format: 2 rdba: 0x0380e573
last change scn: 0x0288.8e5a2f78 seq: 0x1 flg: 0x04
consistency value in tail: 0x00780601
check value in block header: 0x8739, computed block checksum: 0x2f00
spare1: 0x0, spare2: 0x0, spare3: 0x0
***
Reread of rdba: 0x0380e573 (file 14, block 58739) found same corrupted data
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