DBA常用脚本

1.查询有enqueue等待的事件
SELECT b.SID, b.serial#, b.username, machine, event, wait_time,
CHR (BITAND (p1, -16777216) / 16777215)
|| CHR (BITAND (p1, 16711680) / 65535) "Enqueue Type"
FROM v$session_wait a, v$session b
WHERE a.event NOT LIKE 'SQL*N%'
AND a.event NOT LIKE 'rdbms%'
AND a.SID = b.SID
AND b.SID > 8
AND a.event = 'enqueue'
ORDER BY username;

2

如何确定哪个表空间读写频繁?
select name,phyrds,phywrts,readtim,writetim
from v$filestat a,v$dbfile b
where a.file# = b.file#
order by readtim desc

3

Library Cache Pin/Lock Pile Up

SELECT s.sid, kglpnmod “Mode”, kglpnreq “Req”, SPID “OS Process”
FROM v$session_wait w, x$kglpn p, v$session s ,v$process o
WHERE p.kglpnuse=s.saddr
AND kglpnhdl=w.p1raw
and w.event like ‘%library cache pin%’
and s.paddr=o.addr

4全表扫描的表

SQL>col name for a30

SQL>select name,value from v$sysstat

2 where name in (’table scans(short tables)’,'table scans(long tables)’);

5

查询SQL语句执行时,硬语法分析的次数

select name,value
from v$sysstat
where name like ‘parse count%’;

6

该项显示buffer cache大小是否合适。
公式：1-((physical reads-physical reads direct-physical reads direct (lob)) / session logical reads)
执行：

select 1-((a.value-b.value-c.value)/d.value)

from v$sysstat a,v$sysstat b,v$sysstat c,v$sysstat d

where a.name=’physical reads’ and

b.name=’physical reads direct’ and

c.name=’physical reads direct (lob)’ and

d.name=’session logical reads’;

7

该项显示buffer命中率。
公式：1-(physical reads/ (db block gets+consistent gets))
执行：

select 1 - (sum(decode(name, ‘physical reads’, value, 0)) /

(sum(decode(name, ‘db block gets’, value, 0)) +

sum(decode(name, ‘consistent gets’, value, 0))))

“Buffer Hit Ratio”

from v$sysstat;

8

Soft parse ratio：这项将显示系统是否有太多硬解析。该值将会与原始统计数据对比以确保精确。例如，软解析率仅为0.2则表示硬解析率太高。不过，如果总解析量(parse count total)偏低，这项值可以被忽略。
公式：1 - ( parse count (hard) / parse count (total) )
执行：

select 1-(a.value/b.value)

from v$sysstat a,v$sysstat b

Where a.name=’parse count (hard)’ and b.name=’parse count (total)’;

9

In-memory sort ratio：该项显示内存中完成的排序所占比例。最理想状态下，在OLTP系统中，大部分排序不仅小并且能够完全在内存里完成排序。
公式：sorts (memory) / ( sorts (memory) + sorts (disk) )
执行：

select a.value/(b.value+c.value)

from v$sysstat a,v$sysstat b,v$sysstat c

where a.name=’sorts (memory)’ and

b.name=’sorts (memory)’ and c.name=’sorts (disk)’;

10

Parse to execute ratio：在生产环境，最理想状态是一条sql语句一次解析多数运行。
公式：1 - (parse count/execute count)
执行：

select 1-(a.value/b.value)

from v$sysstat a,v$sysstat b

where a.name=’parse count (total)’ and b.name=’execute count’;

11

Parse CPU to total CPU ratio：该项显示总的CPU花费在执行及解析上的比率。如果这项比率较低，说明系统执行了太多的解析。
公式：1 - (parse time cpu / CPU used by this session)
执行：

select 1-(a.value/b.value)

from v$sysstat a,v$sysstat b

where a.name=’parse time cpu’ and

b.name=’CPU used by this session’;

12

Parse time CPU to parse time elapsed：通常，该项显示锁竞争比率。这项比率计算
是否时间花费在解析分配给CPU进行周期运算(即生产工作)。解析时间花费不在CPU周期运算通常表示由于锁竞争导致了时间花费
公式：parse time cpu / parse time elapsed
执行：

select a.value/b.value

from v$sysstat a,v$sysstat b

where a.name=’parse time cpu’ and b.name=’parse time elapsed’;

13

从V$SYSSTAT获取负载间档(Load Profile)数据
　　负载间档是监控系统吞吐量和负载变化的重要部分，该部分提供如下每秒和每个事务的统计信息：logons cumulative, parse count (total), parse count (hard), executes, physical reads, physical writes, block changes, and redo size.
　　被格式化的数据可检查’rates’是否过高，或用于对比其它基线数据设置为识别system profile在期间如何变化。例如，计算每个事务中block changes可用如下公式：

db block changes / ( user commits + user rollbacks )
执行：

select a.value/(b.value+c.value)

from v$sysstat a,v$sysstat b,v$sysstat c

where a.name=’db block changes’ and

b.name=’user commits’ and c.name=’user rollbacks’;
其它计算统计以衡量负载方式，如下：

l Blocks changed for each read：这项显示出block changes在block reads中的比例。它将指出是否系统主要用于只读访问或是主要进行诸多数据操作(如：inserts/updates/deletes)
公式：db block changes / session logical reads
执行：

select a.value/b.value

from v$sysstat a,v$sysstat b

where a.name=’db block changes’ and

b.name=’session logical reads’ ;

14

Rows for each sort：
公式：sorts (rows) / ( sorts (memory) + sorts (disk) )
执行：

select a.value/(b.value+c.value)

from v$sysstat a,v$sysstat b,v$sysstat c

where a.name=’sorts (rows)’ and

b.name=’sorts (memory)’ and c.name=’sorts (disk)’;

15

查看某表的约束条件
SQL>select constraint_name, constraint_type,search_condition, r_constraint_name
from user_constraints where table_name = upper(’&table_name’);

SQL>select c.constraint_name,c.constraint_type,cc.column_name
from user_constraints c,user_cons_columns cc
where c.owner = upper(’&table_owner’) and c.table_name = upper(’&table_name’)
and c.owner = cc.owner and c.constraint_name = cc.constraint_name
order by cc.position;

16

查看表空间的名称及大小

select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_size
from dba_tablespaces t, dba_data_files d
where t.tablespace_name = d.tablespace_name
group by t.tablespace_name;

17

查看回滚段名称及大小

select segment_name, tablespace_name, r.status,
(initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent,
max_extents, v.curext CurExtent
From dba_rollback_segs r, v$rollstat v
Where r.segment_id = v.usn(+)
order by segment_name ;

18

查看表空间的使用情况

select sum(bytes)/(1024*1024) as free_space,tablespace_name
from dba_free_space
group by tablespace_name;

SELECT A.TABLESPACE_NAME,A.BYTES TOTAL,B.BYTES USED, C.BYTES FREE,
(B.BYTES*100)/A.BYTES ”% USED”,(C.BYTES*100)/A.BYTES ”% FREE”
FROM SYS.SM$TS_AVAIL A,SYS.SM$TS_USED B,SYS.SM$TS_FREE C
WHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME AND A.TABLESPACE_NAME=C.TABLESPACE_NAME;

19

当移动一个表的多个分区时的脚本

BEGIN
FOR x IN (SELECT partition_name
FROM user_tab_partitions
WHERE table_name = ‘BIG_TABLE2′)
LOOP
EXECUTE IMMEDIATE ‘alter table big_table2 move partition ‘
|| x.partition_name;
END LOOP;
END;
/

20

查看LOCK

SELECT /*+ ORDERED USE_HASH(H,R) */
H.SID HOLD_SID,
R.SID WAIT_SID,
decode(H.type,
”MR”, ”Media Recovery”,
”RT”, ”Redo Thread”,
”UN”, ”User Name”,
”TX”, ”Transaction”,
”TM”, ”DML”,
”UL”, ”PL/SQL User Lock”,
”DX”, ”Distributed Xaction”,
”CF”, ”Control File”,
”IS”, ”Instance State”,
”FS”, ”File Set”,
”IR”, ”Instance Recovery”,
”ST”, ”Disk Space Transaction”,
”TS”, ”Temp Segment”,
”IV”, ”Library Cache Invalidation”,
”LS”, ”Log Start or Switch”,
”RW”, ”Row Wait”,
”SQ”, ”Sequence Number”,
”TE”, ”Extend Table”,
”TT”, ”Temp Table”,
H.type) type,
decode(H.lmode,
0, ”None”, 1, ”Null”,
2, ”Row-S (SS)”, 3, ”Row-X (SX)”,
4, ”Share”, 5, ”S/Row-X (SSX)”,
6, ”Exclusive”, to_char(H.lmode)) hold,
decode(r.request, 0, ”None”,
1, ”Null”, 2, ”Row-S (SS)”,
3, ”Row-X (SX)”, 4, ”Share”,
5, ”S/Row-X (SSX)”,6, ”Exclusive”,
to_char(R.request)) request,
R.ID1,R.ID2,R.CTIME
FROM VLOCK H,VLOCK R
WHERE H.BLOCK = 1 AND R.BLOCK=0

and H.TYPE <> ”MR” AND R.TYPE <> ”MR”
AND H.ID1 = R.ID1 AND H.ID2 = R.ID2

21

查看ORACLE运行的OS平台
SQL> run
1 begin
2 dbms_output.put_line(
3 dbms_utility.port_string);
4* end;
Linuxi386/Linux-2.0.34-8.1.0

PL/SQL 过程已成功完成。

22

查看空间详细使用情况

CREATE OR REPLACE PROCEDURE show_space (
p_segname IN VARCHAR2,
p_owner IN VARCHAR2 DEFAULT USER,
p_type IN VARCHAR2 DEFAULT 'TABLE',
p_partition IN VARCHAR2 DEFAULT NULL
)
AS
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;

PROCEDURE p (p_label IN VARCHAR2, p_num IN NUMBER)
IS
BEGIN
DBMS_OUTPUT.put_line (RPAD (p_label, 40, '.') || p_num);
END;
BEGIN
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_lastusedextblocki

last_used_block => l_last_used_block
);
p ('Total Blocks', l_total_blocks);
p ('Total Bytes', l_total_bytes);
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;
/

24

显示缓冲区的相关SQL

SELECT tch, file#, dbablk,
CASE
WHEN obj = 4294967295
THEN 'rbs/compat segment'
ELSE (SELECT MAX ( '('
|| object_type
|| ') '
|| owner
|| '.'
|| object_name
)
|| DECODE (COUNT (*), 1, '', ' maybe!')
FROM dba_objects
WHERE data_object_id = x.obj)
END what
FROM (SELECT tch, file#, dbablk, obj
FROM x$bh
WHERE state <> 0
ORDER BY tch DESC) x
WHERE ROWNUM <= 5;

25

获取生成的根据文件名
select c.value ||'/' || d.instance_name || '_ora_' ||a.spid || '.trc' trace
from v$process a,v$session b,v$parameter c,v$instance d
where a.addr=b.paddr
and b.audsid=userenv('sessionid')
and c.name='user_dump_dest'
/

在v$session_longops视图中，sofar字段表示已经扫描的块数，totalwork表示总得需要扫描的块数，所以我们即可以对正在运行的长查询进行监控，比如在索引创建时，查看索引创建的进度，也可以查看系统中以往的长查询。。。

col opname format a32
col target_desc format a32
col perwork format a12
set lines 131
select sid,OPNAME,TARGET_DESC,sofar,TOTALWORK,trunc(sofar/totalwork*100,2)||'%' as perwork
from v$session_longops where sofar!=totalwork;

set lines 121
set pages 999
col opname format a29
col target format a29
col target_desc format a12
col perwork format a12
col remain format 99
col start_time format a21
col sofar format 99999999
col totalwork format 99999999
col sql_text format a101
col bufgets format 99999999

select opname,target,to_char(start_time,'yy-mm-dd:hh24:mi:ss') start_time,elapsed_seconds elapsed,
executions execs,buffer_gets/decode(executions,0,1,executions) bufgets,module,sql_text
from v$session_longops sl,v$sqlarea sa
where sl.sql_hash_value = sa.hash_value and upper(substr(module,1,4)) <> 'RMAN' and substr(opname,1,4) <> 'RMAN'
and module <> 'SQL*Plus' and sl.start_time>trunc(sysdate)
order by start_time;

1. 监控事例的等待
select event,sum(decode(wait_Time,0,0,1)) "Prev", sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
from v$session_Wait group by event order by 4;
2. 回滚段的争用情况
select name, waits, gets, waits/gets "Ratio" from v$rollstat a, v$rollname b where a.usn = b.usn;
3. 监控表空间的 I/O 比例
select df.tablespace_name name,df.file_name "file",f.phyrds pyr, f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw from v$filestat f, dba_data_files df where f.file# = df.file_id order by df.tablespace_name;
4. 监控文件系统的 I/O 比例
select substr(a.file#,1,2) "#", substr(a.name,1,30) "Name", a.status, a.bytes, b.phyrds, b.phywrts from v$datafile a, v$filestat b where a.file# = b.file#;
5.在某个用户下找所有的索引
select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name from user_ind_columns, user_indexes where user_ind_columns.index_name = user_indexes.index_name and user_ind_columns.table_name = user_indexes.table_name order by user_indexes.table_type, user_indexes.table_name, user_indexes.index_name, column_position;
6. 监控 SGA 的命中率
select a.value + b.value "logical_reads", c.value "phys_reads", round(100 * ((a.value+b.value)-c.value) / (a.value+b.value)) "BUFFER HIT RATIO" from v$sysstat a, v$sysstat b, v$sysstat c where a.statistic# = 38 and b.statistic# = 39 and c.statistic# = 40;
7. 监控 SGA 中字典缓冲区的命中率
select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio", (1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio" from v$rowcache where gets+getmisses <>0 group by parameter, gets, getmisses;
8. 监控 SGA 中共享缓存区的命中率，应该小于1%
select sum(pins) "Total Pins", sum(reloads) "Total Reloads", sum(reloads)/sum(pins) *100 libcache from v$librarycache; select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent" from v$librarycache;9. 显示所有数据库对象的类别和大小 select count(name) num_instances ,type ,sum(source_size) source_size , sum(parsed_size) parsed_size ,sum(code_size) code_size ,sum(error_size) error_size, sum(source_size) +sum(parsed_size) +sum(code_size) +sum(error_size) size_required from dba_object_size group by type order by 2;
10. 监控 SGA 中重做日志缓存区的命中率，应该小于1% SELECT name, gets, misses, immediate_gets, immediate_misses, Decode(gets,0,0,misses/gets*100) ratio1, Decode(immediate_gets+immediate_misses,0,0, immediate_misses/(immediate_gets+immediate_misses)*100) ratio2 FROM v$latch WHERE name IN ('redo allocation', 'redo copy');
11. 监控内存和硬盘的排序比率，最好使它小于 .10，增加 sort_area_size
SELECT name, value FROM v$sysstat WHERE name IN ('sorts (memory)', 'sorts (disk)');
12. 监控当前数据库谁在运行什么SQL语句
SELECT osuser, username, sql_text from v$session a, v$sqltext b where a.sql_address =b.address order by address, piece;
13. 监控字典缓冲区
SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE; SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE; SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM

V$LIBRARYCACHE; 后者除以前者,此比率小于1%,接近0%为好。 SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES" FROM V$ROWCACHE
14. 找ORACLE字符集
select * from sys.props$ where name='NLS_CHARACTERSET';
15. 监控 MTS
select busy/(busy+idle) "shared servers busy" from v$dispatcher; 此值大于0.5时，参数需加大 select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where type='dispatcher'; select count(*) from v$dispatcher; select servers_highwater from v$mts; servers_highwater接近mts_max_servers时，参数需加大
16. 碎片程度
select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name having count(tablespace_name)>10; alter tablespace name coalesce; alter table name deallocate unused; create or replace view ts_blocks_v as select tablespace_name,block_id,bytes,blocks,'free space' segment_name from dba_free_space union all select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents; select * from ts_blocks_v; select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space group by tablespace_name; 查看碎片程度高的表 SELECT segment_name table_name , COUNT(*) extents FROM dba_segments WHERE owner NOT IN ('SYS', 'SYSTEM') GROUP BY segment_name HAVING COUNT(*) = (SELECT MAX( COUNT(*) ) FROM dba_segments GROUP BY segment_name);
17. 表、索引的存储情况检查
select segment_name,sum(bytes),count(*) ext_quan from dba_extents where tablespace_name='&tablespace_name' and segment_type='TABLE' group by tablespace_name,segment_name; select segment_name,count(*) from dba_extents where segment_type='INDEX' and owner='&owner' group by segment_name;18、找使用CPU多的用户session 12是cpu used by this session select a.sid,spid,status,substr(a.program,1,40) prog,a.terminal,osuser,value/60/100 value from v$session a,v$process b,v$sesstat c where c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;

寻找CPU使用过量的session ，找出高CPU利用率的SQL：

 

SELECT /*+ ORDERED */
sql_text
FROM v$sqltext a
WHERE (a.hash_value, a.address) IN
(SELECT decode(sql_hash_value, 0, prev_hash_value, sql_hash_value), decode(sql_hash_value, 0, prev_sql_addr, sql_address)
FROM v$session b
WHERE b.paddr = (SELECT addr
FROM v$process c
WHERE c.spid = '&pid'))
ORDER BY piece ASC;