常用SQL語句

SQL> 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;
檢視錶空間物理檔案的名稱及大小:

SQL> SELECT TABLESPACE_NAME,FILE_ID,FILE_NAME,ROUND(BYTES / (1024 * 1024), 0) TOTAL_SPACE
FROM DBA_DATA_FILES
ORDER BY TABLESPACE_NAME;
檢視回滾段名稱及大小:
SQL> 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$ROLLSTAT V
WHERE R.SEGMENT_ID = V.USN(+)
ORDER BY SEGMENT_NAME;
如何檢視某個回滾段裡面，跑的什麼事物或者正在執行什麼sql語句:
SQL> SELECT D.SQL_TEXT, A.NAME
FROM V$ROLLNAME A, V$TRANSACTION B, V$SESSION C, V$SQLTEXT D
WHERE A.USN = B.XIDUSN
AND B.ADDR = C.TADDR
AND C.SQL_ADDRESS = D.ADDRESS
AND C.SQL_HASH_VALUE = D.HASH_VALUE
AND A.USN = 1;(備註：你要看哪個，就把usn=?寫成幾就行了)

檢視控制檔案:
SQL> SELECT * FROM V$CONTROLFILE;
檢視日誌檔案:
SQL> COL MEMBER FORMAT A50
SQL>SELECT * FROM V$LOGFILE;
如何檢視當前SQL*PLUS使用者的sid和serial#:
SQL>SELECT SID, SERIAL#, STATUS FROM V$SESSION WHERE AUDSID=USERENV('SESSIONID');
如何檢視當前資料庫的字符集:
SQL>SELECT USERENV('LANGUAGE') FROM DUAL;
SQL>SELECT USERENV('LANG') FROM DUAL;

怎麼判斷當前正在使用何種SQL最佳化方式:用EXPLAIN PLAN產生EXPLAIN PLAN¡檢查PLAN_TABLE中ID=0的POSITION列的值
SQL>SELECT DECODE(NVL(POSITION,-1),-1,'RBO',1,'CBO') FROM PLAN_TABLE WHERE ID=0;
如何檢視系統當前最新的SCN號：
SQL>SELECT MAX(KTUXESCNW * POWER(2,32) + KTUXESCNB) FROM X$KTUXE;
在ORACLE中查詢TRACE檔案的指令碼:

SQL>SELECT U_DUMP.VALUE || '/' || INSTANCE.VALUE || '_ORA_' ||
V$PROCESS.SPID || NVL2(V$PROCESS.TRACEID, '_' || V$PROCESS.TRACEID, NULL ) || '.TRC'"TRACE FILE" FROM V$PARAMETER U_DUMP CROSS JOIN V$PARAMETER INSTANCE CROSS JOIN V$PROCESS JOIN V$SESSION ON V$PROCESS.ADDR = V$SESSION.PADDR WHERE U_DUMP.NAME = 'USER_DUMP_DEST' AND
INSTANCE.NAME = 'INSTANCE_NAME' AND V$SESSION.AUDSID=SYS_CONTEXT('USERENV','SESSIONID');

SQL>SELECT D.VALUE || '/ORA_' || P.SPID || '.TRC' TRACE_FILE_NAME
FROM (SELECT P.SPID FROM SYS.V_$MYSTAT M,SYS.V_$SESSION S,
SYS.V_$PROCESS P WHERE M.STATISTIC# = 1 AND
S.SID = M.SID AND P.ADDR = S.PADDR) P,(SELECT VALUE FROM SYS.V_$PARAMETER WHERE NAME ='USER_DUMP_DEST') D;
如何檢視客戶端登陸的IP地址:
SQL>SELECT SYS_CONTEXT('USERENV','IP_ADDRESS') FROM DUAL;
如何在生產資料庫中建立一個追蹤客戶端IP地址的觸發器：
SQL>CREATE OR REPLACE TRIGGER ON_LOGON_TRIGGER AFTER LOGON ON DATABASE
BEGIN
DBMS_APPLICATION_INFO.SET_CLIENT_INFO(SYS_CONTEXT('USERENV', 'IP_ADDRESS'));
END;
REM 記錄登陸資訊的觸發器
CREATE OR REPLACE TRIGGER LOGON_HISTORY
AFTER LOGON ON DATABASE --WHEN (USER='WACOS') --ONLY FOR USER 'WACOS'
BEGIN
INSERT INTO SESSION_HISTORY SELECT USERNAME,SID,SERIAL#,AUDSID,OSUSER,ACTION,SYSDATE,NULL,SYS_CONTEXT('USERENV','IP_ADDRESS'),TERMINAL,MACHINE,PROGRAM FROM V$SESSION WHERE AUDSID = USERENV('SESSIONID');
END;
查詢當前日期:
SQL> SELECT TO_CHAR(SYSDATE,'YYYY-MM-DD,HH24:MI:SS') FROM DUAL;
檢視所有表空間對應的資料檔名：

SQL>SELECT DISTINCT FILE_NAME,TABLESPACE_NAME,AUTOEXTENSIBLE FROM DBA_DATA_FILES;
檢視錶空間的使用情況:
SQL>SELECT SUM(BYTES)/(1024*1024) AS FREE_SPACE,TABLESPACE_NAME
FROM DBA_FREE_SPACE GROUP BY TABLESPACE_NAME;

SQL>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;

COLUMN TABLESPACE_NAME FORMAT A18;
COLUMN SUM_M FORMAT A12;
COLUMN USED_M FORMAT A12;
COLUMN FREE_M FORMAT A12;
COLUMN PTO_M FORMAT 9.99;

SELECT S.TABLESPACE_NAME,CEIL(SUM(S.BYTES/1024/1024))||'M' SUM_M,CEIL(SUM(S.USEDSPACE/1024/1024))||'M' USED_M,CEIL(SUM(S.FREESPACE/1024/1024))||'M' FREE_M, SUM(S.USEDSPACE)/SUM(S.BYTES) PTUSED FROM (SELECT B.FILE_ID,B.TABLESPACE_NAME,B.BYTES, (B.BYTES-SUM(NVL(A.BYTES,0))) USEDSPACE, SUM(NVL(A.BYTES,0)) FREESPACE,(SUM(NVL(A.BYTES,0))/(B.BYTES)) * 100 FREEPERCENTRATIO FROM SYS.DBA_FREE_SPACE A,SYS.DBA_DATA_FILES B WHERE A.FILE_ID(+)=B.FILE_ID GROUP BY B.FILE_ID,B.TABLESPACE_NAME,B.BYTES ORDER BY B.TABLESPACE_NAME) S GROUP BY S.TABLESPACE_NAME ORDER BY SUM(S.FREESPACE)/SUM(S.BYTES) DESC;
檢視資料檔案的hwm（可以resize的最小空間）和檔案頭大小:
SELECT V1.FILE_NAME,V1.FILE_ID,NUM1 TOTLE_SPACE,NUM3 FREE_SPACE,
NUM1-NUM3 "USED_SPACE(HWM)",NVL(NUM2,0) DATA_SPACE,NUM1-NUM3-NVL(NUM2,0) FILE_HEAD
FROM
(SELECT FILE_NAME,FILE_ID,SUM(BYTES) NUM1 FROM DBA_DATA_FILES GROUP BY FILE_NAME,FILE_ID) V1,
(SELECT FILE_ID,SUM(BYTES) NUM2 FROM DBA_EXTENTS GROUP BY FILE_ID) V2,
(SELECT FILE_ID,SUM(BYTES) NUM3 FROM DBA_FREE_SPACE GROUP BY FILE_ID) V3
WHERE V1.FILE_ID=V2.FILE_ID(+) AND V1.FILE_ID=V3.FILE_ID(+);資料檔案大小及頭大小:
SELECT V1.FILE_NAME,V1.FILE_ID,
NUM1 TOTLE_SPACE,
NUM3 FREE_SPACE,
NUM1-NUM3 USED_SPACE,
NVL(NUM2,0) DATA_SPACE,
NUM1-NUM3-NVL(NUM2,0) FILE_HEAD
FROM
(SELECT FILE_NAME,FILE_ID,SUM(BYTES) NUM1 FROM DBA_DATA_FILES GROUP BY FILE_NAME,FILE_ID) V1,
(SELECT FILE_ID,SUM(BYTES) NUM2 FROM DBA_EXTENTS GROUP BY FILE_ID) V2,
(SELECT FILE_ID,SUM(BYTES) NUM3 FROM DBA_FREE_SPACE GROUP BY FILE_ID) V3
WHERE V1.FILE_ID=V2.FILE_ID(+)
AND V1.FILE_ID=V3.FILE_ID(+);
(執行以上查詢，我們可以如下資訊：
Totle_pace:該資料檔案的總大小，位元組為單位
Free_space:該資料檔案的剩於大小，位元組為單位
Used_space:該資料檔案的已用空間，位元組為單位
Data_space:該資料檔案中段資料佔用空間，也就是資料空間，位元組為單位
File_Head:該資料檔案頭部佔用空間，位元組為單位)

資料庫各個表空間增長情況的檢查：
SQL>SELECT A.TABLESPACE_NAME,(1-(A.TOTAL)/B.TOTAL)*100 USED_PERCENT
FROM (SELECT TABLESPACE_NAME,SUM(BYTES) TOTAL FROM DBA_FREE_SPACE GROUP BY TABLESPACE_NAME) A,(SELECT TABLESPACE_NAME,SUM(BYTES) TOTAL FROM DBA_DATA_FILES GROUP BY TABLESPACE_NAME) B WHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME;

SQL>SELECT UPPER(F.TABLESPACE_NAME) "表空間名",
D.TOT_GROOTTE_MB "表空間大小(M)",
D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空間(M)", TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) / D.TOT_GROOTTE_MB * 100, 2), '990.99') "使用比",F.TOTAL_BYTES"空閒空間(M)",
F.MAX_BYTES "最大塊(M)" FROM (SELECT TABLESPACE_NAME,
ROUND(SUM(BYTES) / (1024 * 1024), 2) TOTAL_BYTES,
ROUND(MAX(BYTES) / (1024 * 1024), 2) MAX_BYTES
FROM SYS.DBA_FREE_SPACE GROUP BY TABLESPACE_NAME) F,
(SELECT DD.TABLESPACE_NAME,ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB FROM SYS.DBA_DATA_FILES DD
GROUP BY DD.TABLESPACE_NAME) D WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME
ORDER BY 4 DESC;
檢視各個表空間佔用磁碟情況:
SQL>COL TABLESPACE_NAME FORMAT A20;
SQL>SELECT B.FILE_ID FILE_ID,
B.TABLESPACE_NAME TABLESPACE_NAME,
B.BYTES BYTES,
(B.BYTES-SUM(NVL(A.BYTES,0))) USED,
SUM(NVL(A.BYTES,0)) FREE,
SUM(NVL(A.BYTES,0))/(B.BYTES)*100 PERCENT
FROM DBA_FREE_SPACE A,DBA_DATA_FILES B
WHERE A.FILE_ID=B.FILE_ID
GROUP BY B.TABLESPACE_NAME,B.FILE_ID,B.BYTES
ORDER BY B.FILE_ID;
資料庫物件下一擴充套件與表空間的free擴充套件值的檢查：
SQL>SELECT A.TABLE_NAME, A.NEXT_EXTENT, A.TABLESPACE_NAME
FROM ALL_TABLES A,(SELECT TABLESPACE_NAME, MAX(BYTES) AS BIG_CHUNK
FROM DBA_FREE_SPACE GROUP BY TABLESPACE_NAME ) F WHERE F.TABLESPACE_NAME = A.TABLESPACE_NAME AND A.NEXT_EXTENT > F.BIG_CHUNK
UNION SELECT A.INDEX_NAME, A.NEXT_EXTENT, A.TABLESPACE_NAME
FROM ALL_INDEXES A,(SELECT TABLESPACE_NAME, MAX(BYTES) AS BIG_CHUNK
FROM DBA_FREE_SPACE GROUP BY TABLESPACE_NAME ) F WHERE F.TABLESPACE_NAME = A.TABLESPACE_NAME AND A.NEXT_EXTENT > F.BIG_CHUNK;
Disk Read最高的SQL語句的獲取：
SQL>SELECT SQL_TEXT FROM (SELECT * FROM V$SQLAREA ORDER BY DISK_READS)
WHERE ROWNUM<=5;
查詢前十條效能差的sql
SELECT * FROM (SELECT PARSING_USER_ID
EXECUTIONS,SORTS,COMMAND_TYPE,DISK_READS,
SQL_TEXT FROM V$SQLAREA ORDER BY DISK_READS DESC)
WHERE ROWNUM<10 ;
等待時間最多的5個系統等待事件的獲取：
SQL>SELECT * FROM (SELECT * FROM V$SYSTEM_EVENT WHERE EVENT NOT LIKE 'SQL%' ORDER BY TOTAL_WAITS DESC) WHERE ROWNUM<=5;
檢視當前等待事件的會話:
COL USERNAME FORMAT A10
SET LINE 120
COL EVENT FORMAT A30
SELECT SE.SID,S.USERNAME,SE.EVENT,SE.TOTAL_WAITS,SE.TIME_WAITED,SE.AVERAGE_WAIT
FROM V$SESSION S,V$SESSION_EVENT SE WHERE S.USERNAME IS NOT NULL AND SE.SID=S.SID
AND S.STATUS='ACTIVE' AND SE.EVENT NOT LIKE '%SQL*NET%';

SELECT SID, EVENT, P1, P2, P3, WAIT_TIME, SECONDS_IN_WAIT, STATE FROM V$SESSION_WAIT WHERE EVENT NOT LIKE '%MESSAGE%' AND EVENT NOT LIKE 'SQL*NET%' AND EVENT NOT LIKE '%TIMER%' AND EVENT != 'WAKEUP TIME MANAGER';
找到與所連線的會話有關的當前等待事件：

SELECT SW.SID,S.USERNAME,SW.EVENT,SW.WAIT_TIME,SW.STATE,SW.SECONDS_IN_WAIT SEC_IN_WAIT
FROM V$SESSION S,V$SESSION_WAIT SW WHERE S.USERNAME IS NOT NULL AND SW.SID=S.SID
AND SW.EVENT NOT LIKE '%SQL*NET%' ORDER BY SW.WAIT_TIME DESC;
Oracle所有回滾段狀態的檢查：

SQL>SELECT SEGMENT_NAME,OWNER,TABLESPACE_NAME,INITIAL_EXTENT,NEXT_EXTENT,DBA_ROLLBACK_SEGS.STATUS FROM DBA_ROLLBACK_SEGS,V$DATAFILE WHERE FILE_ID=FILE#;
Oracle回滾段擴充套件資訊的檢查:
COL NAME FORMAT A10
SET LINESIZE 140
SELECT SUBSTR(NAME,1,40) NAME,EXTENTS,RSSIZE,OPTSIZE,AVEACTIVE,EXTENDS,WRAPS,SHRINKS,HWMSIZE
FROM V$ROLLNAME RN,V$ROLLSTAT RS WHERE (RN.USN=RS.USN);

EXTENTS:回滾段中的盤區數量。Rssize:以位元組為單位的回滾段的尺寸。optsize：為optimal引數設定的值。Aveactive:從回滾段中刪除盤區時釋放的以位元組為單位的平均空間的大小。Extends:系統為回滾段增加的盤區的次數。Shrinks:系統從回滾段中清除盤區（即回滾段收縮）的次數。回滾段每次清除盤區時，系統可能會從這個回滾段中消除一個或多個盤區。Hwmsize:回滾段尺寸的上限，即回滾段曾經達到的最大尺寸。(如果回滾段平均尺寸接近OPTIMAL的值，那麼說明OPTIMAL的值設定正確，如果回滾段動態增長次數或收縮次數很高，那麼需要提高OPTIMAL的值)

檢視回滾段的使用情況，哪個使用者正在使用回滾段的資源:
SELECT S.USERNAME, U.NAME FROM V$TRANSACTION T,V$ROLLSTAT R,
V$ROLLNAME U,V$SESSION S WHERE S.TADDR=T.ADDR AND
T.XIDUSN=R.USN AND R.USN=U.USN ORDER BY S.USERNAME;
如何檢視一下某個shared_server正在忙什麼:
SELECT A.USERNAME,A.MACHINE,A.PROGRAM,A.SID,
A.SERIAL#,A.STATUS,C.PIECE,C.SQL_TEXT
FROM V$SESSION A,V$PROCESS B,V$SQLTEXT C
WHERE B.SPID=13161 AND B.ADDR=A.PADDR
AND A.SQL_ADDRESS=C.ADDRESS(+) ORDER BY C.PIECE;
資料庫共享池效能檢查:
SELECT NAMESPACE,GETS,GETHITRATIO,PINS,PINHITRATIO,RELOADS,INVALIDATIONS FROM V$LIBRARYCACHE WHERE NAMESPACE IN('SQLAREA','TABLE/PROCEDURE','BODY','TRIGGER');
檢查資料過載比率:
SELECT SUM(RELOADS)/SUM(PINS)*100 "RELOAD RATIO" FROM
V$LIBRARYCACHE;
檢查資料字典的命中率:
SELECT 1-SUM(GETMISSES)/SUM(GETS) "DATA DICTIONARY HIT
RATIO" FROM V$ROWCACHE;(對於library cache, gethitratio和pinhitratio應該大於90%,對於資料過載比率,reload ratio應該小於1%,對於資料字典的命中率,data dictionary hit ratio應該大於85%)

檢查共享記憶體的剩餘情況:
SELECT REQUEST_MISSES, REQUEST_FAILURES FROM V$SHARED_POOL_RESERVED; (對於共享記憶體的剩餘情況, request_misses 和request_failures應該接近0)

資料高速緩衝區效能檢查:
SELECT 1-P.VALUE/(B.VALUE+C.VALUE) "DB BUFFER CACHE HIT RATIO" FROM V$SYSSTAT P,V$SYSSTAT B,V$SYSSTAT C WHERE P.NAME='PHYSICAL READS' AND B.NAME='DB BLOCK GETS' AND C.NAME='CONSISTENT GETS';
檢查buffer pool HIT_RATIO執行
SELECT NAME, (PHYSICAL_READS/(DB_BLOCK_GETS+CONSISTENT_GETS)) "MISS_HIT_RATIO" FROM V$BUFFER_POOL_STATISTICS WHERE (DB_BLOCK_GETS+ CONSISTENT_GETS)> 0;(正常時db buffer cache hit ratio 應該大於90%,正常時buffer pool MISS_HIT_RATIO 應該小於10%)

資料庫回滾段效能檢查:檢查Ratio執行
SELECT SUM(WAITS)* 100 /SUM(GETS) "RATIO", SUM(WAITS) "WAITS", SUM(GETS) "GETS" FROM V$ROLLSTAT;
檢查count/value執行:
SELECT CLASS,COUNT FROM V$WAITSTAT WHERE CLASS LIKE '%UNDO%';
SELECT VALUE FROM V$SYSSTAT WHERE NAME='CONSISTENT GETS';(兩者的value值相除)
檢查average_wait執行:
SELECT EVENT,TOTAL_WAITS,TIME_WAITED,AVERAGE_WAIT FROM V$SYSTEM_EVENT WHERE EVENT LIKE '%UNDO%';
檢查RBS header get ratio執行:
SELECT N.NAME,S.USN,S.WRAPS, DECODE(S.WAITS,0,1,1- S.WAITS/S.GETS)"RBS HEADER GET RATIO" FROM V$ROLLSTAT S,V$ROLLNAME N WHERE S.USN=N.USN;(正常時Ratio應該小於1%, count/value應該小於0.01%,average_wait最好為0，該值越小越好,RBS header get ratio應該大於95%)

殺會話的指令碼:
SELECT A.SID,B.SPID,A.SERIAL#,A.LOCKWAIT,A.USERNAME,A.OSUSER,A.LOGON_TIME,A.LAST_CALL_ET/3600 LAST_HOUR,A.STATUS, 'ORAKILL '||SID||' '||SPID HOST_COMMAND,'ALTER SYSTEM KILL SESSION '''||A.SID||','||A.SERIAL#||'''' SQL_COMMAND FROM V$SESSION A,V$PROCESS B WHERE A.PADDR=B.ADDR AND SID>6;
檢視排序段的效能:
SQL>SELECT NAME, VALUE FROM V$SYSSTAT WHERE NAME IN ('SORTS (MEMORY)', 'SORTS (DISK)');
7、檢視資料庫庫物件:
SELECT OWNER, OBJECT_TYPE, STATUS, COUNT(*) COUNT# FROM ALL_OBJECTS GROUP BY OWNER, OBJECT_TYPE, STATUS;
8、檢視資料庫的版本:　
SELECT * FROM V$VERSION;
9、檢視資料庫的建立日期和歸檔方式:
SELECT CREATED, LOG_MODE, LOG_MODE FROM V$DATABASE;

10、捕捉執行很久的SQL:
COLUMN USERNAME FORMAT A12
COLUMN OPNAME FORMAT A16
COLUMN PROGRESS FORMAT A8
SELECT USERNAME,SID,OPNAME,ROUND(SOFAR*100 / TOTALWORK,0) || '%' AS PROGRESS,TIME_REMAINING,SQL_TEXT FROM V$SESSION_LONGOPS , V$SQL WHERE TIME_REMAINING <> 0 AND SQL_ADDRESS=ADDRESS AND SQL_HASH_VALUE = HASH_VALUE;
11、檢視資料表的引數資訊:
SELECT PARTITION_NAME, HIGH_VALUE, HIGH_VALUE_LENGTH, TABLESPACE_NAME,PCT_FREE, PCT_USED, INI_TRANS, MAX_TRANS, INITIAL_EXTENT,NEXT_EXTENT, MIN_EXTENT, MAX_EXTENT, PCT_INCREASE, FREELISTS,FREELIST_GROUPS, LOGGING, BUFFER_POOL, NUM_ROWS, BLOCKS,EMPTY_BLOCKS, AVG_SPACE, CHAIN_CNT, AVG_ROW_LEN, SAMPLE_SIZE,LAST_ANALYZED FROM DBA_TAB_PARTITIONS--WHERE TABLE_NAME = :TNAME AND TABLE_OWNER = :TOWNER
ORDER BY PARTITION_POSITION;
12、檢視還沒提交的事務:
SELECT * FROM V$LOCKED_OBJECT;
SELECT * FROM V$TRANSACTION;
13、查詢object為哪些程式所用:
SELECT P.SPID,S.SID,S.SERIAL# SERIAL_NUM,S.USERNAME USER_NAME,
A.TYPE OBJECT_TYPE,S.OSUSER OS_USER_NAME,A.OWNER,A.OBJECT OBJECT_NAME,DECODE(SIGN(48 - COMMAND),1,
TO_CHAR(COMMAND), 'ACTION CODE #' || TO_CHAR(COMMAND) ) ACTION,
P.PROGRAM ORACLE_PROCESS,S.TERMINAL TERMINAL,S.PROGRAM PROGRAM,S.STATUS SESSION_STATUS FROM V$SESSION S, V$ACCESS A, V$PROCESS P WHERE S.PADDR = P.ADDR AND S.TYPE = 'USER' AND A.SID = S.SID AND A.OBJECT='SUBSCRIBER_ATTR'ORDER BY S.USERNAME, S.OSUSER;
14、檢視回滾段:
SQL>COL NAME FORMAT A10
SQL>SET LINESIZE 100
SQL>SELECT ROWNUM, SYS.DBA_ROLLBACK_SEGS.SEGMENT_NAME NAME, V$ROLLSTAT.EXTENTS EXTENTS, V$ROLLSTAT.RSSIZE SIZE_IN_BYTES, V$ROLLSTAT.XACTS XACTS, V$ROLLSTAT.GETS GETS, V$ROLLSTAT.WAITS WAITS, V$ROLLSTAT.WRITES WRITES, SYS.DBA_ROLLBACK_SEGS.STATUS STATUS FROM V$ROLLSTAT, SYS.DBA_ROLLBACK_SEGS, V$ROLLNAME WHERE V$ROLLNAME.NAME(+) = SYS.DBA_ROLLBACK_SEGS.SEGMENT_NAME AND V$ROLLSTAT.USN (+) = V$ROLLNAME.USN ORDER BY ROWNUM;
15、耗資源的程式(top session):
SELECT S.SCHEMANAME SCHEMA_NAME,DECODE(SIGN(48 - COMMAND), 1, TO_CHAR(COMMAND), 'ACTION CODE #' || TO_CHAR(COMMAND) ) ACTION,STATUS SESSION_STATUS,S.OSUSER OS_USER_NAME,S.SID,P.SPID,S.SERIAL# SERIAL_NUM,NVL(S.USERNAME,'[ORACLE PROCESS]') USER_NAME,S.TERMINAL TERMINAL,S.PROGRAM PROGRAM,ST.VALUE CRITERIA_VALUE FROM V$SESSTAT ST,V$SESSION S,V$PROCESS P WHERE ST.SID = S.SID AND ST.STATISTIC# = TO_NUMBER('38') AND ('ALL'='ALL' OR S.STATUS ='ALL') AND P.ADDR=S.PADDR ORDER BY ST.VALUE DESC,P.SPID ASC,S.USERNAME ASC,S.OSUSER ASC;
根據PID查詢相應的語句:

SELECT A.USERNAME, A.MACHINE,A.PROGRAM,A.SID,A.SERIAL#,A.STATUS,C.PIECE,C.SQL_TEXT FROM V$SESSION A,V$PROCESS B,V$SQLTEXT C WHERE B.SPID=SPID AND B.ADDR=A.PADDR AND A.SQL_ADDRESS=C.ADDRESS(+) ORDER BY C.PIECE;