本篇内容主要讲解“v$transaction中有哪些回滚段信息”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“v$transaction中有哪些回滚段信息”吧!

SQL>select*fromv$rollnameawherea.usn=6;USNNAME----------------------------------------6_SYSSMU6_3707530756$SQL>selectusn,writes,rssize,xacts,hwmsize,shrinks,wrapsfromv$rollstat;USNWRITESRSSIZEXACTSHWMSIZESHRINKSWRAPS----------------------------------------------------------------------081123850240385024001800750222003202220032032141234022200320222003201313988662220032022200320341569748222003202220032045210938432686080326860804648775485365760153657600971672696222003202220032028134193822200320222003201915427522220032022200320510187943243171840431718402

altersystemdumpundoheader'_SYSSMU6$';转储undo块头

转储内容：

[oracle@parnassusdata1trace]$tail-n300PROD1_ora_10132.trcTracefile/s01/oracle/app/oracle/diag/rdbms/prod/PROD1/trace/PROD1_ora_10132.trcOracleDatabase11gEnterpriseEditionRelease11.2.0.4.0-64bitProductionWiththePartitioning,RealApplicationClusters,AutomaticStorageManagement,OLAP,DataMiningandRealApplicationTestingoptionsORACLE_HOME=/s01/oracle/app/oracle/product/11.2.0/dbhome_1Systemname:LinuxNodename:parnassusdata1.oracle.comRelease:2.6.32-200.13.1.el5uekVersion:#1SMPWedJul2721:02:33EDT2011Machine:x86_64Instancename:PROD1Redothreadmountedbythisinstance:1Oracleprocessnumber:50Unixprocesspid:10132,image:oracle@parnassusdata1.oracle.com(TNSV1-V3)***2018-09-1702:18:24.629***SESSIONID:(77.73)2018-09-1702:18:24.629***CLIENTID:()2018-09-1702:18:24.629***SERVICENAME:(SYS$USERS)2018-09-1702:18:24.629***MODULENAME:(SQL*Plus)2018-09-1702:18:24.629***ACTIONNAME:()2018-09-1702:18:24.629********************************************************************************UndoSegment:_SYSSMU6_3707530756$(6)********************************************************************************ExtentControlHeader-----------------------------------------------------------------ExtentHeader::spare1:0spare2:0#extents:7#blocks:655lastmap0x00000000#maps:0offset:4080Highwater::0x00c00a47ext#:4blk#:71extsize:128#blocksinseg.hdr'sfreelists:0#blocksbelow:0mapblk0x00000000offset:4UnlockedMapHeader::next0x00000000#extents:7obj#:0flag:0x40000000ExtentMap-----------------------------------------------------------------0x00c000d1length:70x00c000d8length:80x00c00800length:1280x00c00980length:1280x00c00a00length:1280x00c00280length:1280x00c00700length:128RetentionTable-----------------------------------------------------------ExtentNumber:0CommitTime:1537121357ExtentNumber:1CommitTime:1537121357ExtentNumber:2CommitTime:1537121357ExtentNumber:3CommitTime:1537121357ExtentNumber:4CommitTime:1537121357ExtentNumber:5CommitTime:1537121357ExtentNumber:6CommitTime:1537121357TRNCTL::seq:0x0232chd:0x001dctl:0x000ainc:0x00000000nfb:0x0000mgc:0xb000xts:0x0068flg:0x0001opt:2147483646(0x7ffffffe)uba:0x00c00a47.0232.2dscn:0x0000.006d9937Version:0x01FREEBLOCKPOOL::uba:0x00000000.0232.2cext:0x4spc:0x836uba:0x00000000.022c.28ext:0x2spc:0xad6uba:0x00000000.022c.09ext:0x2spc:0x4d0uba:0x00000000.0218.01ext:0x2spc:0x1f84uba:0x00000000.0092.01ext:0x18spc:0x1ed0TRNTBL::indexstatecflagswrap#uelscndbaparent-xidnubstmt_numcmt------------------------------------------------------------------------------------------------0x0090x000x09720x00020x0000.006d999d0x00c00a460x0000.000.000000000x000000010x0000000015371213590x0190x000x096f0x00050x0000.006d9a630x00c00a470x0000.000.000000000x000000010x0000000015371213590x0290x000x09710x001c0x0000.006d99aa0x00c00a460x0000.000.000000000x000000010x0000000015371213590x0390x000x09700x001f0x0000.006d9af10x00c00a470x0000.000.000000000x000000010x0000000015371213590x0490x000x09750x000d0x0000.006d9aa30x00c00a470x0000.000.000000000x000000010x0000000015371213590x0590x000x09720x00060x0000.006d9a720x00c00a470x0000.000.000000000x000000010x0000000015371213590x0690x000x09700x00070x0000.006d9a810x00c00a470x0000.000.000000000x000000010x0000000015371213590x0790x000x09680x00040x0000.006d9a920x00c00a470x0000.000.000000000x000000010x0000000015371213590x0890x000x096f0x001a0x0000.006d99e80x00c00a470x0000.000.000000000x000000010x0000000015371213590x0990x000x09720x00000x0000.006d99900x00c00a460x0000.000.000000000x000000010x0000000015371213590x0a90x000x09730xffff0x0000.006d9b440x00c00a470x0000.000.000000000x000000010x0000000015371213940x0b90x000x09720x000f0x0000.006d9a410x00c00a470x0000.000.000000000x000000010x0000000015371213590x0c90x000x09740x00090x0000.006d99820x00c00a460x0000.000.000000000x000000010x0000000015371213590x0d90x000x09740x00190x0000.006d9ab30x00c00a470x0000.000.000000000x000000010x0000000015371213590x0e90x000x09700x00080x0000.006d99da0x00c00a470x0000.000.000000000x000000010x0000000015371213590x0f90x000x08bc0x00010x0000.006d9a520x00c00a470x0000.000.000000000x000000010x0000000015371213590x1090x000x09710x00140x0000.006d9a230x00c00a470x0000.000.000000000x000000010x0000000015371213590x1190x000x09740x000a0x0000.006d9b390x00c00a470x0000.000.000000000x000000010x0000000015371213940x1290x000x096e0x00130x0000.006d9a060x00c00a470x0000.000.000000000x000000010x0000000015371213590x1390x000x096f0x00100x0000.006d9a150x00c00a470x0000.000.000000000x000000010x0000000015371213590x1490x000x09730x000b0x0000.006d9a330x00c00a470x0000.000.000000000x000000010x0000000015371213590x1590x000x09710x000c0x0000.006d99720x00c00a460x0000.000.000000000x000000010x0000000015371213590x16100x800x096e0x00040x0000.006d9b4f0x00c00a470x0000.000.000000000x000000010x0000000000x1790x000x096e0x00030x0000.006d9ae30x00c00a470x0000.000.000000000x000000010x0000000015371213590x1890x000x09700x00110x0000.006d9b2d0x00c00a470x0000.000.000000000x000000010x0000000015371213940x1990x000x096f0x00210x0000.006d9ac30x00c00a470x0000.000.000000000x000000010x0000000015371213590x1a90x000x09710x00120x0000.006d99f80x00c00a470x0000.000.000000000x000000010x0000000015371213590x1b90x000x09700x00200x0000.006d99520x00c00a460x0000.000.000000000x000000010x0000000015371213590x1c90x000x09710x001e0x0000.006d99bb0x00c00a460x0000.000.000000000x000000010x0000000015371213590x1d90x000x09720x001b0x0000.006d99450x00c00a460x0000.000.000000000x000000010x0000000015371213590x1e90x000x09720x000e0x0000.006d99cc0x00c00a470x0000.000.000000000x000000010x0000000015371213590x1f90x000x09730x00180x0000.006d9b110x00c00a470x0000.000.000000000x000000010x0000000015371213610x2090x000x09700x00150x0000.006d99620x00c00a460x0000.000.000000000x000000010x0000000015371213590x2190x000x096f0x00170x0000.006d9ad40x00c00a470x0000.000.000000000x000000010x000000001537121359EXTTRNCTL::usn:6sp1:0x00000000sp2:0x00000000sp3:0x00000000sp4:0x00000000sp5:0x00000000sp6:0x00000000sp7:0x00000000sp8:0x00000000EXTTRNTBL::indexextflagextHashextSpare1extSpare2---------------------------------------------------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

分析关键信息：

0x16100x800x096e0x00040x0000.006d9b4f0x00c00a470x0000.000.000000000x000000010x000000000

状态（State）为 10 代表的是活动事务，该事务正好占用的是第 22 号事务槽(0x16)

[oracle@parnassusdata1trace]$printf%d0x1723[oracle@parnassusdata1trace]$printf%d0x1622[oracle@parnassusdata1trace]$

DBA（Data Block Address），这个 DBA 指向的就是包含这个事务的前镜像的数据块地址:

0x00c00a47

DBA 代表数据块的存储地址，由 10 位文件号 + 22 位数据块（Block）组成。

先把16变10

8388693[oracle@parnassusdata1 trace]$ printf %d 0x00c00a47

12585543

然后将

前面用0补齐32位

00000000110000000000101001000111

经过转换后，该前镜像信息位于 file3 block 2631。

这和我们从事务表中查询得到的数据完全一致：

SQL>SELECTxidusn,xidslot,xidsqn,ubablk,ubafil,ubarecFROMv$transaction;XIDUSNXIDSLOTXIDSQNUBABLKUBAFILUBAREC------------------------------------------------------------62224142631345

说明前进行位于 3号文件，2631数据块

get新技能：

[oracle@parnassusdata1trace]$printf%d0x1723[oracle@parnassusdata1trace]$printf%d0x1622[oracle@parnassusdata1trace]$

到此，相信大家对“v$transaction中有哪些回滚段信息”有了更深的了解，不妨来实际操作一番吧！这里是亿速云网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！