DBA常用資料庫管理SQL (摘錄整理)

select bytes/1024/1024,TABLESPACE_NAME from dba_free_space where tablespace_name='MES_USER' ORDER BY BYTES DESC
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*************  查詢chained row ****************************
select table_name , chain_cnt from user_tables order by chain_cnt desc ;
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*************查詢當前執行的sql****************************
select a.username,a.machine,a.program,b.spid,c.sql_text from v$session a,v$process b,v$sqlarea c
where a.paddr=b.addr and  c.hash_value=a.sql_hash_value and c.address=a.sql_address and b.spid=
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*************查詢當前執行的程式****************************
select a.username,a.machine,a.program,b.spid,a.serial#,a.sid from v$session a,v$process b
where a.paddr=b.addr and b.spid in ()

select a.username,a.machine,a.program,b.spid,a.serial#,a.sid from v$session a,v$process b
where a.paddr=b.addr and a.sid in ()

SELECT a.machine,a.terminal,a.osuser, a.username, b.sql_text
from v$session a, v$sqlarea b, v$process  c
where a.sql_address =b.address  and  a.paddr=c.addr
      and c.spid in ()
order by b.address

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kill session
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SELECT sid, serial#, username
FROM v$session

  SID   SERIAL# USERNAME
----- --------- ----------------
    1         1
    2         1
    3         1
    4         1
    5         1
    7         1
    8        28 OPS$BQUIGLEY
   10       211 OPS$SWIFT
   11        39 OPS$OBRIEN
   12        13 SYSTEM 
   13         8 SCOTT

The following statement kills the session of the user scott using the SID and SERIAL# values from V$SESSION:

ALTER SYSTEM KILL SESSION '13, 8';

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Linux 下kill Pid
kill -9 pid 

windows orakill

C:>orakill

Usage:  orakill sid thread

  where sid    = the Oracle instance to target
        thread = the thread id of the thread to kill

  The thread id should be retrieved from the spid column of a query such as:

        select spid, osuser, s.program from
        v$process p, v$session s where p.addr=s.paddr

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*************檢視資料庫中物件空間是否成幾何增長***************

select * from dba_segments where pct_increase='50' and owner not in ('SYS','SYSTEM')

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*************檢視當前使用者使用的操作****************************

SELECT a.machine,a.terminal,a.osuser, a.username, b.sql_text
from v$session a, v$sqlarea b
where a.sql_address =b.address order by b.address

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*************監控事例的等待**************************** 

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;

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2. 回滾段的使用情況

select name, waits, gets, waits/gets "Ratio"
from v$rollstat a, v$rollname b
where a.usn = b.usn;
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3. 監控表空間的 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;
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4. 監控檔案系統的 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#;
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5.在某個使用者下找所有的索引

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;

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6. 監控 SGA 的命中率 (data buffer)

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;
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7. 監控 SGA 中字典緩衝區的命中率

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;
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8. 監控 SGA 中共享快取區的命中率，應該小於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;
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9. 顯示所有資料庫物件的類別和大小

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;
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10. 監控 SGA 中重做日誌快取區的命中率，應該小於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'); 

##  Shared pool hit radio
select sum(pinhits)/sum(pins)*100 "shared pool hit radio",sum(reloads)/sum(pins) "reload percent"  from v$librarycache ; 

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11. 監控記憶體和硬碟的排序比率，最好使它小於 .10，增加 sort_area_size

SELECT name, value FROM v$sysstat WHERE name IN ('sorts (memory)', 'sorts (disk)');
The smallest , the best  :     sorts (disk)/(sorts (memory)+sorts (disk)) 
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12. 監控當前資料庫誰在執行什么SQL語句

SELECT osuser, username, sql_text from v$session a, v$sqltext b
where a.sql_address =b.address order by address, piece;

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13. 監控字典緩衝區

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;

後者除以前者,此比率小於1%,接近0%為好。

SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"
FROM V$ROWCACHE

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