[20171113]修改表结构删除列相关问题2.txt
[20171113]修改表结构删除列相关问题2.txt
--//测试看看修改表结构删除列产生的redo向量,对这些操作细节不了解,分析redo看看.
1.环境:
SCOTT@book> @ &r/ver1
PORT_STRING VERSION BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx 11.2.0.4.0 Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
CREATE TABLESPACE TEA DATAFILE
'/mnt/ramdisk/book/tea01.dbf' SIZE 40M AUTOEXTEND ON NEXT 1M MAXSIZE UNLIMITED
LOGGING
ONLINE
EXTENT MANAGEMENT LOCAL AUTOALLOCATE
BLOCKSIZE 8K
SEGMENT SPACE MANAGEMENT MANUAL
FLASHBACK ON;
SCOTT@book> create table t (id number,v1 varchar2(10),v2 varchar2(20)) tablespace tea;
Table created.
SCOTT@book> insert into t select rownum,lpad('a',10,'a'),lpad('b',20,'b') from xmltable('1 to 3');
3 rows created.
SCOTT@book> commit ;
Commit complete.
2.删除列:
SCOTT@book> alter table t SET UNUSED (v1);
Table altered.
SCOTT@book> alter system archive log current ;
System altered.
SCOTT@book> set numw 12
SCOTT@book> select current_scn from v$database ;
CURRENT_SCN
------------
13277730224
SCOTT@book> @ &r/logfile
GROUP# STATUS TYPE MEMBER IS_ GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME
------ ---------- ---------- -------------------------------- --- ------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ -------------------
1 ONLINE /mnt/ramdisk/book/redo01.log NO 1 1 791 52428800 512 1 NO CURRENT 13277730193 2017-11-13 10:11:22 2.814750E+14
2 ONLINE /mnt/ramdisk/book/redo02.log NO 2 1 789 52428800 512 1 YES INACTIVE 13277727924 2017-11-13 09:48:48 13277728003 2017-11-13 09:48:53
3 ONLINE /mnt/ramdisk/book/redo03.log NO 3 1 790 52428800 512 1 YES ACTIVE 13277728003 2017-11-13 09:48:53 13277730193 2017-11-13 10:11:22
4 STANDBY /mnt/ramdisk/book/redostb01.log NO
5 STANDBY /mnt/ramdisk/book/redostb02.log NO
6 STANDBY /mnt/ramdisk/book/redostb03.log NO
7 STANDBY /mnt/ramdisk/book/redostb04.log NO
7 rows selected.
--//当前redo是/mnt/ramdisk/book/redo01.log.
SCOTT@book> ALTER TABLE t DROP UNUSED COLUMNS ;
Table altered.
SCOTT@book> select current_scn from v$database ;
CURRENT_SCN
------------
13277730365
SCOTT@book> alter system dump logfile '/mnt/ramdisk/book/redo01.log' scn min 13277730224 scn max 13277730365;
System altered.
3.分析转储看看:
SCOTT@book> SELECT OBJ#,col#, segcol#, name, intcol#, type# FROM sys.col$ WHERE obj# IN (SELECT object_id FROM dba_objects WHERE object_name = 'T' AND owner = user);
OBJ# COL# SEGCOL# NAME INTCOL# TYPE#
------------ ------------ ------------ ---- ------- ------------
90617 1 1 ID 1 2
90617 2 2 V2 2 1
$ grep OBJ:90617 /u01/app/oracle/diag/rdbms/book/book/trace/book_ora_47196.trc
CHANGE #3 TYP:2 CLS:1 AFN:6 DBA:0x01800081 OBJ:90617 SCN:0x0003.176a14f9 SEQ:5 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800081 OBJ:90617 SCN:0x0003.176a162e SEQ:1 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800081 OBJ:90617 SCN:0x0003.176a162e SEQ:2 OP:11.14 ENC:0 RBL:0
--//看到3次修改.
SCOTT@book> select rowid,t.* from t ;
ROWID ID V2
------------------ ------------ --------------------
AAAWH5AAGAAAACBAAA 1 bbbbbbbbbbbbbbbbbbbb
AAAWH5AAGAAAACBAAB 2 bbbbbbbbbbbbbbbbbbbb
AAAWH5AAGAAAACBAAC 3 bbbbbbbbbbbbbbbbbbbb
SCOTT@book> @ &r/rowid AAAWH5AAGAAAACBAAA
OBJECT FILE BLOCK ROW ROWID_DBA DBA TEXT
------------ ------------ ------------ ------------ -------------------- -------------------- ----------------------------------------
90617 6 129 0 0x1800081 6,129 alter system dump datafile 6 block 129 ;
--//摘取其中1段:
REDO RECORD - Thread:1 RBA: 0x000317.0000009c.0084 LEN: 0x017c VLD: 0x01
SCN: 0x0003.176a162e SUBSCN: 1 11/13/2017 10:13:57
CHANGE #1 TYP:0 CLS:35 AFN:3 DBA:0x00c00110 OBJ:4294967295 SCN:0x0003.176a1592 SEQ:1 OP:5.2 ENC:0 RBL:0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ktudh redo: slt: 0x0009 sqn: 0x0000532a flg: 0x0012 siz: 132 fbi: 0
uba: 0x00c1cd3c.10c6.10 pxid: 0x0000.000.00000000
CHANGE #2 TYP:0 CLS:36 AFN:3 DBA:0x00c1cd3c OBJ:4294967295 SCN:0x0003.176a1591 SEQ:1 OP:5.1 ENC:0 RBL:0
ktudb redo: siz: 132 spc: 3916 flg: 0x0012 seq: 0x10c6 rec: 0x10
xid: 0x000a.009.0000532a
ktubl redo: slt: 9 rci: 0 opc: 11.1 [objn: 90617 objd: 90617 tsn: 7]
Undo type: Regular undo Begin trans Last buffer split: No
Temp Object: No
Tablespace Undo: No
0x00000000 prev ctl uba: 0x00c1cd3c.10c6.0f
prev ctl max cmt scn: 0x0003.176a1392 prev tx cmt scn: 0x0003.176a1396
txn start scn: 0xffff.ffffffff logon user: 83 prev brb: 12700985 prev bcl: 0 BuExt idx: 0 flg2: 0
KDO undo record:
KTB Redo
op: 0x03 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: Z
KDO Op code: DSC row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x01800081 hdba: 0x01800080
itli: 2 ispac: 0 maxfr: 4863
tabn: 0 slot: 0(0x0)
piece relative column number: 1
CHANGE #3 TYP:2 CLS:1 AFN:6 DBA:0x01800081 OBJ:90617 SCN:0x0003.176a14f9 SEQ:5 OP:11.14 ENC:0 RBL:0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
KTB Redo
op: 0x11 ver: 0x01
compat bit: 4 (post-11) padding: 1
op: F xid: 0x000a.009.0000532a uba: 0x00c1cd3c.10c6.10
Block cleanout record, scn: 0x0003.176a162e ver: 0x01 opt: 0x02, entries follow...
itli: 1 flg: 2 scn: 0x0003.176a14f9
KDO Op code: DSC row dependencies Disabled
xtype: XA flags: 0x00000000 bdba: 0x01800081 hdba: 0x01800080
itli: 2 ispac: 0 maxfr: 4863
tabn: 0 slot: 0(0x0)
piece relative column number: 1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--//突然想起我以前的一次测试,链接http://blog.itpub.net/267265/viewspace-2081924/=>[20160414]分析drop column.txt
--//做这个操作是实际上row directory是不动.后面字段的信息往前移动
SCOTT@book> @ &r/bbvi 6 129
BVI_COMMAND
---------------------------------------------------
bvi -b 1056768 -s 8192 /mnt/ramdisk/book/tea01.dbf
$ bvi -b 1056768 -s 8192 /mnt/ramdisk/book/tea01.dbf
...
00103F80 5F 51 01 01 2A 02 00 01 FA 12 2C 02 02 02 C1 02 _Q..*.....,.....
00103F90 14 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 .bbbbbbbbbbbbbbb
00103FA0 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 bbbbbbbbbbbbbbbb
00103FB0 2C 02 02 02 C1 03 14 62 62 62 62 62 62 62 62 62 ,......bbbbbbbbb
00103FC0 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 bbbbbbbbbbbbbbbb
00103FD0 62 62 62 62 62 62 2C 02 02 02 C1 04 14 62 62 62 bbbbbb,......bbb
00103FE0 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 62 bbbbbbbbbbbbbbbb
00103FF0 62 62 62 62 62 62 62 62 62 62 62 62 01 06 35 16 bbbbbbbbbbbb..5.
00104000
--//可以发现前面的一串aaaaaa被覆盖了.
3.重复测试:
SCOTT@book> create table t1 (id number,v1 varchar2(10),v2 varchar2(10),v3 varchar2(10),v4 varchar2(10),v5 varchar2(50)) tablespace tea;
Table created.
SCOTT@book> insert into t1 select rownum,lpad('c',10,'c'),lpad('d',10,'d'),lpad('e',10,'e'),lpad('f',10,'f'),lpad('e',50,'e') from xmltable('1 to 4');
4 rows created.
SCOTT@book> commit ;
Commit complete.
SCOTT@book> SELECT obj#,col#, segcol#, name, intcol#, type# FROM sys.col$ WHERE obj# IN (SELECT object_id FROM dba_objects WHERE object_name = 'T1' AND owner = user);
OBJ# COL# SEGCOL# NAME INTCOL# TYPE#
----- ---- ------------ ---- ------- ------------
90620 1 1 ID 1 2
90620 2 2 V1 2 1
90620 3 3 V2 3 1
90620 4 4 V3 4 1
90620 5 5 V4 5 1
90620 6 6 V5 6 1
6 rows selected.
SCOTT@book> select rowid,t1.* from t1 where rownum=1 ;
ROWID ID V1 V2 V3 V4 V5
------------------ ------------ ---------- ---------- ---------- ---------- --------------------------------------------------
AAAWH8AAGAAAACJAAA 1 cccccccccc dddddddddd eeeeeeeeee ffffffffff eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
SCOTT@book> @ &r/rowid AAAWH8AAGAAAACJAAA
OBJECT FILE BLOCK ROW ROWID_DBA DBA TEXT
------------ ------------ ------------ ------------ -------------------- -------------------- ----------------------------------------
90620 6 137 0 0x1800089 6,137 alter system dump datafile 6 block 137 ;
2.删除列:
$ cat a.sql
alter table t1 SET UNUSED (v2,v4);
SELECT obj#,col#, segcol#, name, intcol#, type# FROM sys.col$ WHERE obj# IN (SELECT object_id FROM dba_objects WHERE object_name = 'T1' AND owner = user);
alter system archive log current ;
@ &r/logfile
select current_scn from v$database ;
ALTER TABLE t1 DROP UNUSED COLUMNS ;
select current_scn from v$database ;
SELECT obj#,col#, segcol#, name, intcol#, type# FROM sys.col$ WHERE obj# IN (SELECT object_id FROM dba_objects WHERE object_name = 'T1' AND owner = user);
SCOTT@book> @a.sql
Table altered.
OBJ# COL# SEGCOL# NAME INTCOL# TYPE#
---------- ---------- ---------- -------------------- ---------- ----------
90620 1 1 ID 1 2
90620 2 2 V1 2 1
90620 0 3 SYS_C00003_17111311: 3 1
01:01$
90620 3 4 V3 4 1
90620 0 5 SYS_C00005_17111311: 5 1
01:01$
90620 4 6 V5 6 1
6 rows selected.
System altered.
GROUP# STATUS TYPE MEMBER IS_ GROUP# THREAD# SEQUENCE# BYTES BLOCKSIZE MEMBERS ARC STATUS FIRST_CHANGE# FIRST_TIME NEXT_CHANGE# NEXT_TIME
------ ---------- ---------- -------------------------------- --- ------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ -------------------
1 ONLINE /mnt/ramdisk/book/redo01.log NO 1 1 791 52428800 512 1 YES INACTIVE 13277730193 2017-11-13 10:11:22 13277732831 2017-11-13 10:46:55
2 ONLINE /mnt/ramdisk/book/redo02.log NO 2 1 792 52428800 512 1 YES ACTIVE 13277732831 2017-11-13 10:46:55 13277734072 2017-11-13 11:01:01
3 ONLINE /mnt/ramdisk/book/redo03.log NO 3 1 793 52428800 512 1 NO CURRENT 13277734072 2017-11-13 11:01:01 2.814750E+14
4 STANDBY /mnt/ramdisk/book/redostb01.log NO
5 STANDBY /mnt/ramdisk/book/redostb02.log NO
6 STANDBY /mnt/ramdisk/book/redostb03.log NO
7 STANDBY /mnt/ramdisk/book/redostb04.log NO
7 rows selected.
CURRENT_SCN
------------
13277734075
Table altered.
CURRENT_SCN
------------
13277734087
OBJ# COL# SEGCOL# NAME INTCOL# TYPE#
------------ ------------ ------------ -------------------- ------------ ------------
90620 1 1 ID 1 2
90620 2 2 V1 2 1
90620 3 3 V3 3 1
90620 4 4 V5 4 1
--//可以发现OBJ#没有变化.
SYS@book> alter system dump logfile '/mnt/ramdisk/book/redo03.log' scn min 13277734075 scn max 13277734087;
System altered.
$ grep "OBJ:90620" /u01/app/oracle/diag/rdbms/book/book/trace/book_ora_47804.trc
CHANGE #3 TYP:2 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a2294 SEQ:5 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a24bc SEQ:1 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a24bc SEQ:2 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a24bc SEQ:3 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a24bc SEQ:4 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a24bc SEQ:5 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a24bc SEQ:6 OP:11.14 ENC:0 RBL:0
CHANGE #2 TYP:0 CLS:1 AFN:6 DBA:0x01800089 OBJ:90620 SCN:0x0003.176a24bc SEQ:7 OP:11.14 ENC:0 RBL:0
--//可以看到改动8次,我实际上SET UNUSED (v2,v4),2个字段.
$ grep "piece relative column number:" /u01/app/oracle/diag/rdbms/book/book/trace/book_ora_47804.trc
piece relative column number: 2
piece relative column number: 2
piece relative column number: 3
piece relative column number: 3
piece relative column number: 2
piece relative column number: 2
piece relative column number: 3
piece relative column number: 3
piece relative column number: 2
piece relative column number: 2
piece relative column number: 3
piece relative column number: 3
piece relative column number: 2
piece relative column number: 2
piece relative column number: 3
piece relative column number: 3
--//注:我故意加回车分开.
--//注意piece relative column number的变化,说明oracle是一条一条记录修改,修改表T1的第2字段做删除操作,然后删除V4字段(注这个是否片的相对行号就是3,而不是4)
--//出现16次,其中一半是undo的记录.
[20171113]修改表结构删除列相关问题2.txt的更多相关文章
- [20171113]修改表结构删除列相关问题4.txt
[20171113]修改表结构删除列相关问题4.txt --//连续写了3篇修改表结构删除列的相关问题,链接如下: http://blog.itpub.net/267265/viewspace-214 ...
- [20171113]修改表结构删除列相关问题3.txt
[20171113]修改表结构删除列相关问题3.txt --//维护表结构删除字段一般都是先ALTER TABLE <table_name> SET UNUSED (<column_ ...
- [20171113]修改表结构删除列相关问题.txt
[20171113]修改表结构删除列相关问题.txt --//维护表结构删除字段一般都是先ALTER TABLE <table_name> SET UNUSED (<column_n ...
- mysql在线修改表结构大数据表的风险与解决办法归纳
整理这篇文章的缘由: 互联网应用会频繁加功能,修改需求.那么表结构也会经常修改,加字段,加索引.在线直接在生产环境的表中修改表结构,对用户使用网站是有影响. 以前我一直为这个问题头痛.当然那个时候不需 ...
- oracle 11g 通过在线重定义方式修改表结构
今天因为要对一套数据库的数据抽取进行io优化,希望通过修改表结构将抽取io降下来,因为抽取只针对标签HAVE_FLAG为"0"的值进行抽取,抽取之后更新HAVE_FLAG为其他值, ...
- 必须会的SQL语句（二） 创建表、修改表结构、删除表
1.创建数据库表 --使用哪个数据库,如果不写这一句是默认的数据库,也可以用鼠标选当前数据库 use testDB --创建表 Create Table tablename ( ...
- SQL Server -- 回忆笔记（二）：增删改查，修改表结构，约束，关键字使用，函数，多表联合查询
SQL Server知识点回忆篇(二):增删改查,修改表结构,约束,关键字使用,函数,多表联合查询 1. insert 如果sql server设置的排序规则不是简体中文,必须在简体中文字符串前加N, ...
- (转)pt-online-schema-change在线修改表结构
原文:http://www.ywnds.com/?p=4442 一.背景 MySQL大字段的DDL操作:加减字段.索引.修改字段属性等,在5.1之前都是非常耗时耗力的,特别是会对MySQL服务产生影响 ...
- SQL Server 修改表结构（转载）
SQL Server 修改表结构 本文链接:https://blog.csdn.net/petezh/article/details/81744374 查看指定表结构 exec sp_help Rep ...
随机推荐
- 12-部署EFK插件
配置和安装 EFK 官方文件目录:cluster/addons/fluentd-elasticsearch $ ls *.yaml es-controller.yaml es-service.yaml ...
- [EXP]Microsoft Windows MSHTML Engine - "Edit" Remote Code Execution
# Exploit Title: Microsoft Windows (CVE-2019-0541) MSHTML Engine "Edit" Remote Code Execut ...
- c/c++本地时间获取
在记录程序日志时,需要记录时间.如下: #include <iostream> #include <time.h> #include <windows.h> usi ...
- Linux编程 6 (查看进程 ps 及输出风格)
一．查看进程命令ps 1.1 默认ps 命令 在默认情况下,ps命令只会显示运行在当前控制台下,属于当前用户的进程,在上图中,我们只运行了bash shell以及ps命令本身. 上图中显示了程序的进程 ...
- 从零开始学 Web 之 DOM（五）元素的创建
大家好,这里是「 从零开始学 Web 系列教程 」,并在下列地址同步更新...... +-------------------------------------------------------- ...
- Velocity常用语法详解
果然公司用的东西跟平时学的东西不太一样,我们公司前台页面并不是我们熟悉的.html或者.jsp文件,而是很多人不知道的 .vm文件,其实只要我们理解了jsp文件,vm文件也就是一些基本语法不同而已. ...
- （转）深度学习目标检测指标mAP
深度学习目标检测指标mAP https://github.com/rafaelpadilla/Object-Detection-Metrics 参考上面github链接中的readme,有详细描述
- 自动化发布-GitLab WEB Hooks 配置
钩子(hooks) hooks是在特定事件发生之前或之后执行特定脚本代码功能(从概念上类比,就与监听事件.触发器之类的东西类似). Git hooks就是那些在Git执行特定事件(如commit.pu ...
- go sync.once用法
欢迎关注go语言微信公众号 每日go语言 golang_everyday sync.once可以控制函数只能被调用一次.不能多次重复调用.示例代码: package main import ( &qu ...
- hiveServer2 和 metastore的一点解读。
刚看了hive官网的文档,对于一些概念结合自己的经验,似乎又多了一些理解,想一想还是记下来的好,一来我是个有些健忘的人,过一段时间即便忘了,循着这个帖子,也能快速把知识点抓起来:二来或许对别人也有些启 ...