ORACLE checkpoint cnt和checkpoint scn
刚才上网搜checkpoint cnt，看到EYGLE写的一篇文章，写得不错，存起来方便以后学习。
=========================================================================
通过试验说明checkpoint cnt 和checkpoint scn的关系
1.在不同条件下转储控制文件
SQL> alter session set events 'immediate trace name CONTROLF level 10';
Session altered.
SQL> alter tablespace system begin backup;
Tablespace altered.
SQL> alter session set events 'immediate trace name CONTROLF level 10';
Session altered.
SQL> alter system checkpoint;
System altered.
SQL> alter session set events 'immediate trace name CONTROLF level 10'
2 /
Session altered.
SQL> alter tablespace system end backup;
Tablespace altered.
SQL> alter session set events 'immediate trace name CONTROLF level 10';
Session altered.
notes:
alter session set events 'immediate trace name CONTROLF level 10';
用于转储控制文件.
2.获得以下跟踪文件信息(仅研究system表空间记录,请注意红色部分):
a.正常情况下转储控制文件
***************************************************************************
DATA FILE RECORDS
***************************************************************************
(blkno = 0x6, size = 180, max = 100, in-use = 24, last-recid= 574)
DATA FILE #1:
(name #4) /opt/oracle/oradata/hsjf/system01.dbf
creation size=32000 block size=8192 status=0xe head=4 tail=4 dup=1
tablespace 0, index=1 krfil=1 prev_file=0
unrecoverable scn: 0x0000.00000000 04/23/2004 01:20:52
Checkpoint cnt:1567 scn: 0x0000.0148181c 06/22/2004 18:58:46
Stop scn: 0xffff.ffffffff 06/22/2004 18:58:05
Creation Checkpointed at scn: 0x0000.000000ae 07/16/2003 03:40:10
thread:1 rba:(0x1.3.10)
enabled threads: 01000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000
Offline scn: 0x0000.013b46fd prev_range: 0
Online Checkpointed at scn: 0x0000.013b46fe 05/28/2004 23:37:17
thread:1 rba:(0x1.2.0)
enabled threads: 01000000 00000000 00000000 00000000 00000000 00000000
00000000 000
相关文档：
http://www.ej38.com/showinfo/Oracle-108709.html
Oracle 10g statistic数据统计,Oracle会根据这些统计信息来决定是走RBO(Rule-BasedOptimization)，还是走CBO(Cost-BasedOptimization)，会去选择哪种执行计划更划算,影响是否走相关的索引等.如果是CBO的话，它依靠准确的（或者说比较准确的）统计信息来产生优化的� ......
Redo Byte Address (RBA)
Recent entries in the redo thread of an Oracle instance are addressed using a 3-part redo byte address, or RBA. An RBA is comprised of
the log file sequence number (4 bytes)
the log file block number (4 bytes)
the byte offset into the block at which the redo record sta ......
oracle表空间操作详解
一、建立表空间
CREATE TABLESPACE data01
DATAFILE '/oracle/oradata/db/DATA01.dbf' SIZE 500M
UNIFORM SIZE 128k;
二、建立UNDO表空间
CREATE UNDO TABLESPACE UNDOTBS02
DATAFILE '/oracle/oradata/db/UNDOTBS02.dbf' SIZE 50M
#注意：在OPEN状态下某些时刻只能用一个UNDO表空间，如果� ......
分区表维护的常用命令：
ALTER TABLE
-- DROP -- PARTITION
-- ADD |
-- RENAME |
-- MODIFITY |
-- TRUNCATE |
-- SPILT |
-- MOVE |
-- EXCHANGE |
分区索引的常用维护命令：
ALTER INDEX
-- DROP -- PARTITION
-- REBUILD |
-- RENAME |
-- MODIFITY |
-- SPILT |
-- PARALLEL
-- UNUSABLE
1、ALTER ......
表空间资料查询
SELECT tablespace_name, block_size, extent_management, segment_space_management from dba_tablespaces;
配和
SELECT tablespace_name, initial_extent, next_extent, max_extents, pct_increase, min_extlen from dba_tablespaces;
配合
SEL ......
