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ORACLE DBA常用语句和脚本

原创 Linux操作系统 作者:xz43 时间:2011-01-28 12:55:40 0 删除 编辑

一, 常用到的设置环境参数的语句
设置SCOTT/TIGER的DEMO
运行@ORACLE_HOME/sqlplus/demo/demobld.sql (响应的demodrop.sql.是DROP SCOTT的脚本)
做一个登陆用的login.sql
define _editor=vi
set serveroutput on size 1000000   使DBMS_OUTPUT有效.
set trimspool on          SPOOL不会以定长来控制,而是以空格来控制
set long 5000                     LONG或CLOG 显示的长度
set linesize 100
set pagesize 9999        每9999行后打印HEAD
column plan_plus_exp format a80         autotrace后explain plan output的格式
column global_name new_value gname
set termout off
define gname=idle
column global_name new_value gname
select lower(user) || '@' || substr( global_name, 1,
decode( dot, 0, length(global_name), dot-1) ) global_name
from (select global_name, instr(global_name,'.') dot from global_name );
set sqlprompt '&gname> '
set termout on
set trimspool on;  去除重定向(spool)输出每行的拖尾空格,缺省为off
得到username@dbname的提示符.      scott@WWMDB>
二, 常用到的DBA脚本
Runstats 比较两个作相同事情的方法的优劣点。本包统计三个值,一个是时间(不重要,由于手工运行,而且偏差较大),二,使用内存方面,三,LATCH。
开发人员经常在自己的PC上装DB,然后进行开发,这些脚本的目的就是让开发人员可以观察自己的SQL是如何运行的以及效率如何.
create or replace view stats
as select 'STAT...' || a.name name, b.value
from v$statname a, v$mystat b
where a.statistic# = b.statistic#
union all
select 'LATCH.' || name, gets
from v$latch;
 
create global temporary table run_stats
( runid varchar2(15),
name varchar2(80),
value int )
on commit preserve rows;
 
create or replace package runstats_pkg
 as
 procedure rs_start;                      --运行操作之前
 procedure rs_middle;                   --运行第一个操作之后
 procedure rs_stop( p_difference_threshold in number default 0 );          --结束                 --p_difference_threshold        控制多大差别才予以输出。
 end;
create or replace package body runstats_pkg
 as
 g_start number;   --全局变量。
 g_run1 number;
 g_run2 number;
procedure rs_start               --清空以前的统计信息
 is
 begin
 delete from run_stats;             ---清空
 insert into run_stats
 select 'before', stats.* from stats;
 g_start := dbms_utility.get_time;
 end;
procedure rs_middle            --记录第一个SQL运行时间,STATISTIC,LATCH
 is
 begin
 g_run1 := (dbms_utility.get_time-g_start);
 insert into run_stats
 select 'after 1', stats.* from stats;
 g_start := dbms_utility.get_time;
 end;
 procedure rs_stop(p_difference_threshold in number default 0)
 is
 begin
 g_run2 := (dbms_utility.get_time-g_start);
 dbms_output.put_line
 ( 'Run1 ran in ' || g_run1 || ' hsecs' );
 dbms_output.put_line
 ( 'Run2 ran in ' || g_run2 || ' hsecs' );
 dbms_output.put_line
 ( 'run 1 ran in ' || round(g_run1/g_run2*100,2) ||
 '% of the time' );
 dbms_output.put_line( chr(9) );
 insert into run_stats
 select 'after 2', stats.* from stats;
 dbms_output.put_line
 ( rpad( 'Name', 30 ) || lpad( 'Run1', 10 ) ||
lpad( 'Run2', 10 ) || lpad( 'Diff', 10 ) );
 for x in
 ( select rpad( a.name, 30 ) ||
 to_char( b.value-a.value, '9,999,999' ) ||
 to_char( c.value-b.value, '9,999,999' ) ||
 to_char( ( (c.value-b.value)-(b.value-a.value)), '9,999,999' ) data
 from run_stats a, run_stats b, run_stats c
 where a.name = b.name
 and b.name = c.name
 and a.runid = 'before'
 and b.runid = 'after 1'
 and c.runid = 'after 2'
 and (c.value-a.value) > 0
 and abs( (c.value-b.value) - (b.value-a.value) )
 > p_difference_threshold
 order by abs( (c.value-b.value)-(b.value-a.value))
 ) loop
 dbms_output.put_line( x.data );
 end loop;
 dbms_output.put_line( chr(9) );
 dbms_output.put_line
 ( 'Run1 latches total versus runs -- difference and pct' );
 dbms_output.put_line
 ( lpad( 'Run1', 10 ) || lpad( 'Run2', 10 ) ||
 lpad( 'Diff', 10 ) || lpad( 'Pct', 8 ) );
 for x in
 ( select to_char( run1, '9,999,999' ) ||
 to_char( run2, '9,999,999' ) ||
 to_char( diff, '9,999,999' ) ||
 to_char( round( run1/run2*100,2 ), '999.99' ) || '%' data
 from ( select sum(b.value-a.value) run1, sum(c.value-b.value) run2,
 sum( (c.value-b.value)-(b.value-a.value)) diff
 from run_stats a, run_stats b, run_stats c
 where a.name = b.name
 and b.name = c.name
 and a.runid = 'before'
 and b.runid = 'after 1'
 and c.runid = 'after 2'
 and a.name like 'LATCH%'
 )
 ) loop
 dbms_output.put_line( x.data );
 end loop;
 end;
end;
/
      测试
SQL> create table wwm as select * from all_objects where 1=2;
表已创建。
SQL> create table wwm2 as select * from all_objects where 1=2;
表已创建。
SQL> exec runstats_pkg.rs_start;
PL/SQL 过程已成功完成。
SQL> insert into wwm select * from all_objects;
已创建34750行。
SQL> exec runstats_pkg.rs_middle;
PL/SQL 过程已成功完成。
然后用第二种方法,一行一行地插入。
SQL> begin
  2  for x in (select * from all_objects)
  3  loop
  4     insert into wwm2 values x;
  5  end loop;
  6  commit;
  7  end;
  8  /
---------------( create procedure p( ENAME in varchar2 )
as
begin
for x in ( select * from emp where ename = ENAME ) loop
Dbms_output.put_line( x.empno );
end loop;
end;
-----------------
SQL> exec runstats_pkg.rs_stop(1000000)
Run1 ran in 3558 hsecs
Run2 ran in 14263 hsecs
run 1 ran in 24.95% of the time
Name                                Run1      Run2      Diff
STAT...session pga memory              0 4,040,516 4,040,516
STAT...session pga memory max          0 4,064,632 4,064,632
STAT...session pga memory max          0 4,064,632 4,064,632
STAT...session pga memory              0 4,106,052 4,106,052
STAT...redo size               3,920,896########## 8,291,688
STAT...redo size               3,920,896########## 8,352,408
 
Run1 latches total versus runs -- difference and pct
Run1      Run2      Diff     Pct
305,006 1,462,079 1,157,073  20.86%
三, Mystat   统计某操作之前和之后的变化。
Mystat.sql脚本捕捉初始值
set echo off
set verify off
column value new_val V
define S="&1"
输入 1 的值:  redo size                --可以输入不同的值来判断不同的指标
set autotrace off
select a.name, b.value
from v$statname a, v$mystat b
where a.statistic# = b.statistic#
and lower(a.name) like '%' || lower('&S')||'%'
/
NAME                VALUE
-----------------------------
redo size         16408460
set echo on
中间做需要统计的操作。
  1* update wwm set object_name=lower(object_name)
SQL> /
已更新34750行。
mystat2脚本报告异同点。
set echo off
set verify off
select a.name, b.value V, to_char(b.value-&V,'999,999,999,999') diff
from v$statname a, v$mystat b
where a.statistic# = b.statistic#
and lower(a.name) like '%' || lower('&S')||'%'
NAME                    V        DIFF
------------------------------------
redo size         26028120        9,619,660
可以看到这次UPDATE产生了9,619,660  bytes of redo.

四, Show_space 统计SEGMENT的空间使用具体情况。
create or replace procedure show_space
( p_segname in varchar2,                    --SGEMENT的NAME
p_owner in varchar2 default user,                      --默任是当前用户
p_type in varchar2 default 'TABLE',           --SEGMENT 的TYPE
p_partition in varchar2 default NULL )         --PARTITION的NAME
-- this procedure uses authid current user so it can query DBA_*
-- views using privileges from a ROLE, and so it can be installed
-- once per database, instead of once per user who wanted to use it
authid current_user
as
l_free_blks number;
l_total_blocks number;
l_total_bytes number;
l_unused_blocks number;
l_unused_bytes number;
l_LastUsedExtFileId number;
l_LastUsedExtBlockId number;
l_LAST_USED_BLOCK number;
l_segment_space_mgmt varchar2(255);
l_unformatted_blocks number;
l_unformatted_bytes number;
l_fs1_blocks number; l_fs1_bytes number;
l_fs2_blocks number; l_fs2_bytes number;
l_fs3_blocks number; l_fs3_bytes number;
l_fs4_blocks number; l_fs4_bytes number;
l_full_blocks number; l_full_bytes number;
-- inline procedure to print out numbers nicely formatted
-- with a simple label
procedure p( p_label in varchar2, p_num in number )
is
begin
dbms_output.put_line( rpad(p_label,40,'.') ||
to_char(p_num,'999,999,999,999') );
end;
begin
-- this query is executed dynamically in order to allow this procedure
-- to be created by a user who has access to DBA_SEGMENTS/TABLESPACES
-- via a role as is customary.
-- NOTE: at runtime, the invoker MUST have access to these two
-- views!
-- this query determines if the object is an ASSM object or not
begin
execute immediate
'select ts.segment_space_management
from dba_segments seg, dba_tablespaces ts
where seg.segment_name = :p_segname
and (:p_partition is null or
seg.partition_name = :p_partition)
and seg.owner = :p_owner
and seg.tablespace_name = ts.tablespace_name'
into l_segment_space_mgmt
using p_segname, p_partition, p_partition, p_owner;
exception
when too_many_rows then
dbms_output.put_line
( 'This must be a partitioned table, use p_partition => ');
return;
end;
-- if the object is in an ASSM tablespace, we must use this API
-- call to get space information, otherwise we use the FREE_BLOCKS
-- API for the user-managed segments
if l_segment_space_mgmt = 'AUTO'
then
dbms_space.space_usage
( p_owner, p_segname, p_type, l_unformatted_blocks,
l_unformatted_bytes, l_fs1_blocks, l_fs1_bytes,
l_fs2_blocks, l_fs2_bytes, l_fs3_blocks, l_fs3_bytes,
l_fs4_blocks, l_fs4_bytes, l_full_blocks, l_full_bytes, p_partition);
p( 'Unformatted Blocks ', l_unformatted_blocks );
p( 'FS1 Blocks (0-25) ', l_fs1_blocks );
p( 'FS2 Blocks (25-50) ', l_fs2_blocks );
p( 'FS3 Blocks (50-75) ', l_fs3_blocks );
p( 'FS4 Blocks (75-100)', l_fs4_blocks );
p( 'Full Blocks ', l_full_blocks );
else
dbms_space.free_blocks(
segment_owner => p_owner,
segment_name => p_segname,
segment_type => p_type,
freelist_group_id => 0,
free_blks => l_free_blks);
p( 'Free Blocks', l_free_blks );
end if;
-- and then the unused space API call to get the rest of the
-- information
dbms_space.unused_space
( segment_owner => p_owner,
segment_name => p_segname,
segment_type => p_type,
partition_name => p_partition,
total_blocks => l_total_blocks,
total_bytes => l_total_bytes,
unused_blocks => l_unused_blocks,
unused_bytes => l_unused_bytes,
LAST_USED_EXTENT_FILE_ID => l_LastUsedExtFileId,
LAST_USED_EXTENT_BLOCK_ID => l_LastUsedExtBlockId,
LAST_USED_BLOCK => l_LAST_USED_BLOCK );
p( 'Total Blocks', l_total_blocks );
p( 'Total Bytes', l_total_bytes );
p( 'Total MBytes', trunc(l_total_bytes/1024/1024) );
p( 'Unused Blocks', l_unused_blocks );
p( 'Unused Bytes', l_unused_bytes );
p( 'Last Used Ext FileId', l_LastUsedExtFileId );
p( 'Last Used Ext BlockId', l_LastUsedExtBlockId );
p( 'Last Used Block', l_LAST_USED_BLOCK );
end;
 
SQL> desc show_space
PROCEDURE show_space
参数名称                       类型                    输入/输出默认值?
------------------------------ ----------------------- ------ --------
 P_SEGNAME                      VARCHAR2                IN
 P_OWNER                        VARCHAR2                IN     DEFAULT
 P_TYPE                         VARCHAR2                IN     DEFAULT
 P_PARTITION                    VARCHAR2                IN     DEFAULT
ASSM和user space managed tablespaces得到的结果不同,以下用user space managed tablespaces来说明
SQL> exec show_spacE('WWM');
Free Blocks.............................               2
Total Blocks............................           5,120
Total Bytes.............................      41,943,040
Total MBytes............................              40
Unused Blocks...........................              13
Unused Bytes............................         106,496
Last Used Ext FileId....................               1
Last Used Ext BlockId...................          46,473
Last Used Block.........................             115
FULL BLOCKS: full表示在没有变化之前不会再被分配出去。
Total Blocks, Total Bytes, Total MBytes: 整个分配给此SEGMENT的空间。
Unused Blocks, Unused Bytes:分配给SEGMENT,但是还没有使用,也就是说在HWM之上的空闲块。
Last Used Ext FileId:  最后一个extent所在的FILE ID.
Last Used Ext BlockId: 最后一个EXTENT 的BEGIN BLOCK ID.
FS1 Blocks–FS4 Blocks: 例如,0-25,表示在0-25%之间的空块.
做一个大表,以供测试使用
create table big_table
as
select rownum id, a.*
from all_objects a
where 1=0
/
alter table big_table nologging;
insert /*+ append */
into big_table
select rownum, a.*
from all_objects a;
已创建29645行。
  1  insert /*+ append */
  2  into big_table
  3  select rownum+29646, a.*
  4* from all_objects a
SQL> /
已创建29645行。
alter table big_table add constraint
big_table_pk primary key(id)
  1  begin
  2  dbms_stats.gather_table_stats
  3  ( wnname => 'SYSTEM',
  4  tabname => 'BIG_TABLE',
  5  method_opt => 'for all indexed columns',
  6  cascade => TRUE );
  7* end;
五, 绑定变量与非绑定变量
阅读本章可以参考我的  BIND VARIABLE
http://sunmoonking.spaces.live.com/blog/cns!E3BD9CBED01777CA!175.entry
测试表
create table t ( x int );
绑定变量
create or replace procedure proc1
 as
begin
for i in 1 .. 10000
loop
execute immediate
'insert into t values ( :x )' using i;
end loop;
 end;
/
非绑定变量
create or replace procedure proc2
 as
 begin
 for i in 1 .. 10000
 loop
 execute immediate
 'insert into t values ( '||i||')';
 end loop;
 end;
/
SQL> exec runstats_pkg.rs_start;
PL/SQL 过程已成功完成。
SQL> exec proc1
PL/SQL 过程已成功完成。
SQL> exec runstats_pkg.rs_middle;
PL/SQL 过程已成功完成。
SQL> exec proc2
PL/SQL 过程已成功完成。
SQL> exec runstats_pkg.rs_stop(1000);    --差别大于1000的才输出
Run1 ran in 1622 hsecs
Run2 ran in 4378 hsecs
run 1 ran in 37.05% of the time
 
Name                                Run1      Run2      Diff
STAT...bytes received via SQL*       387     1,690     1,303
STAT...bytes sent via SQL*Net        276     1,798     1,522
STAT...parse count (hard)              5    10,009    10,004
…………………………………………………………………………….
Run1 latches total versus runs -- difference and pct
Run1      Run2      Diff     Pct
313,680 1,625,995 1,312,315  19.29%
PL/SQL 过程已成功完成。
可以看到PRO2基本上是PRO1的三倍,也就是说解析时间占完整运行完一条语句所耗时间的2/3,会多占用LATCH.可见,尽量减少硬解析能明显提高性能.
六,read-consistent
 
SQL> create table wwm as select * from all_users;
表已创建。
SQL> variable x refcursor
SQL> begin
  2  open :x for select * from wwm;
  3  end;
  4  /
PL/SQL 过程已成功完成。
SQL> delete from wwm;
已删除27行。
SQL> commit;
提交完成。
SQL> print x
USERNAME                                                        USER_ID
------------------------------------------------------------ ----------
CREATED
--------------
BI                                                                   60
07-6月 -06
。。。。。。。。。。。。。。。
注意,这是在一个SESSION里做的实验。现建立一个表WWM,再OPEN一个CURSOR,再DELETE表WWM,甚至COMMIT之后还是可以PRINT CURSOR的原来的内容。
但是,需要明白的是,在OPEN一个CURSOR的时候并不取得数据或把数据放到某个地方;而是在DELETE的时候才将你需要的数据给你保留到一个地方(UNDO SEGMENT或叫ROLLBACK SEGMENT)。
 
七, flashback query.
SCN 是ORACLE内部时钟,
SQL> variable SCN number
SQL> exec :scn:=dbms_flashback.get_system_change_number
PL/SQL 过程已成功完成。
SQL> print scn
       SCN
----------
   1170636
SQL> select count(*) from wwm;
  COUNT(*)
----------
         0
SQL> desc wwm
 名称                                      是否为空? 类型
 ----------------------------------------- -------- ----------------------------
 USERNAME                                  NOT NULL VARCHAR2(30)
 USER_ID                                   NOT NULL NUMBER
 CREATED                                   NOT NULL DATE
SQL> insert into wwm select * from all_users;
已创建27行。
SQL> select count(*) from wwm;
  COUNT(*)
----------
        27
SQL> select count(*) from wwm as of scn :scn;
  COUNT(*)
----------
         0
SQL> commit;
提交完成。
SQL>  select count(*) from wwm as of scn :scn;
  COUNT(*)
----------
         0
甚至,我们可以用一个SQL得到两个SCN点的值
SQL> select * from (select count(*) from wwm),
  2   (select count(*) from wwm as of scn :scn);
 
  COUNT(*)   COUNT(*)
---------- ----------
27                0

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