转发CSDN “郭镇技术BLOG”，用于查看数据库行为

查看表空间的名称及大小:
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;

查看表空间物理文件的名称及大小:
SQL> SELECT TABLESPACE_NAME,FILE_ID,FILE_NAME,ROUND(BYTES / (1024 * 1024), 0) TOTAL_SPACE
FROM DBA_DATA_FILES
ORDER BY TABLESPACE_NAME;

查看回滚段名称及大小:
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;

如何查看某个回滚段里面，跑的什么事物或者正在执行什么sql语句:
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;
(备注：你要看哪个，就把usn=?写成几就行了)

查看控制文件:
SQL> SELECT * FROM V$CONTROLFILE;

查看日志文件:
SQL> COL MEMBER FORMAT A50
SQL>SELECT * FROM V$LOGFILE;

如何查看当前SQL*PLUS用户的sid和serial#:
SQL>SELECT SID, SERIAL#, STATUS FROM V$SESSION WHERE AUDSID=USERENV('SESSIONID');

如何查看当前数据库的字符集:
SQL>SELECT USERENV('LANGUAGE') FROM DUAL;
SQL>SELECT USERENV('LANG') FROM DUAL;


怎么判断当前正在使用何种SQL优化方式:
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;

如何查看系统当前最新的SCN号：
SQL>SELECT MAX(KTUXESCNW * POWER(2,32) + KTUXESCNB) FROM X$KTUXE;

在ORACLE中查找TRACE文件的脚本:
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;

如何查看客户端登陆的IP地址:
SQL>SELECT SYS_CONTEXT('USERENV','IP_ADDRESS') FROM DUAL;

如何在生产数据库中创建一个追踪客户端IP地址的触发器：
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 记录登陆信息的触发器
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;

查询当前日期:
SQL> SELECT TO_CHAR(SYSDATE,'YYYY-MM-DD,HH24:MI:SS') FROM DUAL;

查看所有表空间对应的数据文件名：
SQL>SELECT DISTINCT FILE_NAME,TABLESPACE_NAME,AUTOEXTENSIBLE FROM DBA_DATA_FILES;

查看表空间的使用情况:
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;

查看数据文件的hwm（可以resize的最小空间）和文件头大小:
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(+);

数据文件大小及头大小:
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(+);

(运行以上查询，我们可以如下信息：
Totle_pace:该数据文件的总大小，字节为单位
Free_space:该数据文件的剩于大小，字节为单位
Used_space:该数据文件的已用空间，字节为单位
Data_space:该数据文件中段数据占用空间，也就是数据空间，字节为单位
File_Head:该数据文件头部占用空间，字节为单位)

数据库各个表空间增长情况的检查：
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) "表空间名",
D.TOT_GROOTTE_MB "表空间大小(M)",
       D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空间(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"空闲空间(M)",
       F.MAX_BYTES "最大块(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;

查看各个表空间占用磁盘情况:
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;

数据库对象下一扩展与表空间的free扩展值的检查：
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语句的获取：
SQL>SELECT SQL_TEXT FROM (SELECT * FROM V$SQLAREA ORDER BY DISK_READS)
WHERE ROWNUM<=5;

查找前十条性能差的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 ;

等待时间最多的5个系统等待事件的获取：
SQL>SELECT * FROM (SELECT * FROM V$SYSTEM_EVENT WHERE EVENT NOT LIKE 'SQL%' ORDER BY TOTAL_WAITS DESC) WHERE ROWNUM<=5;

查看当前等待事件的会话:
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';

找到与所连接的会话有关的当前等待事件：

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所有回滚段状态的检查：

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回滚段扩展信息的检查:
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:回滚段中的盘区数量。
Rssize:以字节为单位的回滚段的尺寸。
optsize：为optimal参数设定的值。
Aveactive:从回滚段中删除盘区时释放的以字节为单位的平均空间的大小。
Extends:系统为回滚段增加的盘区的次数。
Shrinks:系统从回滚段中清除盘区（即回滚段收缩）的次数。回滚段每次清除盘区时，系统可能会从这个回滚段中消除一个或多个盘区。
Hwmsize:回滚段尺寸的上限，即回滚段曾经达到的最大尺寸。
(如果回滚段平均尺寸接近OPTIMAL的值，那么说明OPTIMAL的值设置正确，如果回滚段动态增长次数或收缩次数很高，那么需要提高OPTIMAL的值)

查看回滚段的使用情况，哪个用户正在使用回滚段的资源:
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;

如何查看一下某个shared_server正在忙什么:
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;

数据库共享池性能检查:
SELECT NAMESPACE,GETS,GETHITRATIO,PINS,PINHITRATIO,RELOADS,INVALIDATIONS FROM V$LIBRARYCACHE WHERE NAMESPACE IN('SQLAREA','TABLE/PROCEDURE','BODY','TRIGGER');

检查数据重载比率:
SELECT SUM(RELOADS)/SUM(PINS)*100 "RELOAD RATIO" FROM
V$LIBRARYCACHE;

检查数据字典的命中率:
SELECT 1-SUM(GETMISSES)/SUM(GETS) "DATA DICTIONARY HIT
RATIO" FROM V$ROWCACHE;
(对于library cache, gethitratio和pinhitratio应该大于90%,对于数据重载比率,reload ratio应该小于1%,对于数据字典的命中率,data dictionary hit ratio应该大于85%)

检查共享内存的剩余情况:
SELECT REQUEST_MISSES, REQUEST_FAILURES FROM V$SHARED_POOL_RESERVED;
(对于共享内存的剩余情况, request_misses 和request_failures应该接近0)

数据高速缓冲区性能检查:
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';

检查buffer pool HIT_RATIO执行
SELECT NAME, (PHYSICAL_READS/(DB_BLOCK_GETS+CONSISTENT_GETS)) "MISS_HIT_RATIO" FROM V$BUFFER_POOL_STATISTICS WHERE (DB_BLOCK_GETS+ CONSISTENT_GETS)> 0;
(正常时db buffer cache hit ratio 应该大于90%,正常时buffer pool MISS_HIT_RATIO 应该小于10%)

数据库回滚段性能检查:
检查Ratio执行
SELECT SUM(WAITS)* 100 /SUM(GETS) "RATIO", SUM(WAITS) "WAITS", SUM(GETS) "GETS" FROM V$ROLLSTAT;

检查count/value执行:
SELECT CLASS,COUNT FROM V$WAITSTAT WHERE CLASS LIKE '%UNDO%';
SELECT VALUE FROM V$SYSSTAT WHERE NAME='CONSISTENT GETS';
(两者的value值相除)

检查average_wait执行:
SELECT EVENT,TOTAL_WAITS,TIME_WAITED,AVERAGE_WAIT FROM V$SYSTEM_EVENT WHERE EVENT LIKE '%UNDO%';

检查RBS header get ratio执行:
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;
(正常时Ratio应该小于1%, count/value应该小于0.01%,average_wait最好为0，该值越小越好,RBS header get ratio应该大于95%)

杀会话的脚本:
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;

查看排序段的性能:
SQL>SELECT NAME, VALUE FROM V$SYSSTAT WHERE NAME IN ('SORTS (MEMORY)', 'SORTS (DISK)');

7、查看数据库库对象:
SELECT OWNER, OBJECT_TYPE, STATUS, COUNT(*) COUNT# FROM ALL_OBJECTS GROUP BY OWNER, OBJECT_TYPE, STATUS;

8、查看数据库的版本:　
SELECT * FROM V$VERSION;

9、查看数据库的创建日期和归档方式:
SELECT CREATED, LOG_MODE, LOG_MODE FROM V$DATABASE;

10、捕捉运行很久的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、查看数据表的参数信息:
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、查看还没提交的事务:
SELECT * FROM V$LOCKED_OBJECT;
SELECT * FROM V$TRANSACTION;

13、查找object为哪些进程所用:
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、查看回滚段:
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、耗资源的进程(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;

根据PID查找相应的语句:

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;


根据SID找ORACLE的某个进程:
SQL> SELECT PRO.SPID FROM V$SESSION SES,V$PROCESS PRO WHERE SES.SID=21 AND SES.PADDR=PRO.ADDR;

监控当前数据库谁在运行什么SQL语句:
SQL>SELECT OSUSER, USERNAME, SQL_TEXT FROM V$SESSION A, V$SQLTEXT B
WHERE A.SQL_ADDRESS =B.ADDRESS ORDER BY ADDRESS, PIECE;

如何查看数据库中某用户，正在运行什么SQL语句
SQL>SELECT SQL_TEXT FROM V$SQLTEXT T, V$SESSION S WHERE T.ADDRESS=S.SQL_ADDRESS AND T.HASH_VALUE=S.SQL_HASH_VALUE AND S.MACHINE='XXXXX' OR USERNAME='WACOS';

如何查出前台正在发出的sql语句:
SQL> SELECT USER_NAME,SQL_TEXT FROM V$OPEN_CURSOR WHERE SID IN(SELECT SID FROM (SELECT SID,SERIAL# FROM V$SESSION WHERE STATUS='ACTIVE'));

查询当前所执行的SQL语句：
SQL> SELECT PROGRAM ,SQL_ADDRESS FROM V$SESSION WHERE PADDR IN (SELECT ADDR FROM V$PROCESS WHERE SPID=3556);
PROGRAM                                          SQL_ADDRESS
------------------------------------------------ ----------------
SQLPLUS@CTC20 (TNS V1-V3)                        000000038FCB1A90
SQL> SELECT SQL_TEXT FROM V$SQLAREA WHERE ADDRESS='000000038FCB1A90';

找出消耗CPU最高的进程对应的SQL语句：
SET LINE 240
SET VERIFY OFF
COLUMN SID FORMAT 999
COLUMN PID FORMAT 999
COLUMN S_# FORMAT 999
COLUMN USERNAME FORMAT A9 HEADING "ORA USER"
COLUMN PROGRAM FORMAT A29
COLUMN SQL      FORMAT A60
COLUMN OSNAME FORMAT A9 HEADING "OS USER"
SELECT P.PID PID,S.SID SID,P.SPID SPID,S.USERNAME USERNAME,S.OSUSER OSNAME,P.SERIAL# S_#,P.TERMINAL,P.PROGRAM PROGRAM,P.BACKGROUND,S.STATUS,RTRIM(SUBSTR(A.SQL_TEXT, 1, 80)) SQLFROM V$PROCESS P, V$SESSION S,V$SQLAREA A WHERE P.ADDR = S.PADDR AND S.SQL_ADDRESS = A.ADDRESS (+) AND P.SPID LIKE '%&1%';

ENTER VALUE FOR 1: PID¡（这里输入占用CPU最高的进程对应的PID）
SET TERMOUT OFF
SPOOL MAXCPU.TXT
SELECT '++'||S.USERNAME USERNAME,RTRIM(REPLACE(A.SQL_TEXT,CHR(10),''))||';'FROM V$PROCESS P, V$SESSION S,V$SQLAREA A WHERE P.ADDR = S.PADDR AND S.SQL_ADDRESS = A.ADDRESS (+) AND P.SPID LIKE '%&&1%';
Enter value for 1: PID（这里输入占用CPU最高的进程对应的PID）
spool off(这句放在最后执行)

CPU用率最高的2条SQL语句的获取
执行：top，通过top获得CPU占用率最高的进程的pid。
SQL>SELECT SQL_TEXT,SPID,V$SESSION.PROGRAM,PROCESS FROM V$SQLAREA,V$SESSION,V$PROCESS WHERE V$SQLAREA.ADDRESS=V$SESSION.SQL_ADDRESS AND V$SQLAREA.HASH_VALUE=V$SESSION.SQL_HASH_VALUE AND V$SESSION.PADDR=V$PROCESS.ADDR AND V$PROCESS.SPID IN (PID);
COL MACHINE FORMAT A30
COL PROGRAM FORMAT A40
SET LINE 200
SQL>SELECT SID,SERIAL# ,USERNAME,OSUSER,MACHINE,PROGRAM,PROCESS,TO_CHAR(LOGON_TIME,'YYYY/MM/DD HH24:MI:SS') FROM V$SESSION WHERE PADDR IN(SELECT ADDR FROM V$PROCESS WHERE SPID IN([$SPID]));

SELECT SQL_TEXT FROM V$SQLTEXT_WITH_NEWLINES
WHERE HASH_VALUE=(SELECT SQL_HASH_VALUE FROM V$SESSION WHERE SID=&SID)
ORDER BY PIECE;

16、查看锁（lock）情况:
SQL>SELECT /*+ RULE */
LS.OSUSER OS_USER_NAME,
LS.USERNAME USER_NAME,
DECODE(LS.TYPE,
        'RW','ROW WAIT ENQUEUE LOCK',
        'TM','DML ENQUEUE LOCK',
        'TX','TRANSACTION ENQUEUE LOCK',
        'UL','USER SUPPLIED LOCK') LOCK_TYPE,
O.OBJECT_NAME OBJECT,
DECODE(LS.LMODE,
        1,NULL,
        2,'ROW SHARE',
        3,'ROW EXCLUSIVE',
        4,'SHARE',
        5,'SHARE ROW EXCLUSIVE',
        6,'EXCLUSIVE',
        NULL) LOCK_MODE,
O.OWNER,
LS.SID,
LS.SERIAL# SERIAL_NUM,
LS.ID1,
LS.ID2
FROM SYS.DBA_OBJECTS O,
       (SELECT S.OSUSER,
               S.USERNAME,
               L.TYPE,
               L.LMODE,
               S.SID,
               S.SERIAL#,
               L.ID1,
               L.ID2
          FROM V$SESSION S, V$LOCK L
         WHERE S.SID = L.SID) LS
WHERE O.OBJECT_ID = LS.ID1
   AND O.OWNER <> 'SYS'
ORDER BY O.OWNER, O.OBJECT_NAME;

SQL>SELECT SYS.V_$SESSION.OSUSER,
       SYS.V_$SESSION.MACHINE,
       V$LOCK.SID,
       SYS.V_$SESSION.SERIAL#,
       DECODE(V$LOCK.TYPE,
              'MR','MEDIA RECOVERY',
              'RT','REDO THREAD',
              'UN','USER NAME',
              'TX','TRANSACTION',
              'TM','DML',
              'UL','PL/SQL USER LOCK',
              'DX','DISTRIBUTED XACTION',
              'CF','CONTROL FILE',
              'IS','INSTANCE STATE',
              'FS','FILE SET',
              'IR','INSTANCE RECOVERY',
              'ST','DISK SPACE TRANSACTION',
              'TS','TEMP SEGMENT',
              'IV','LIBRARY CACHE INVALIDA-TION',
              'LS','LOG START OR SWITCH',
              'RW','ROW WAIT',
              'SQ','SEQUENCE NUMBER',
              'TE','EXTEND TABLE',
              'TT','TEMP TABLE',
              'UNKNOWN') LOCKTYPE,
       RTRIM(OBJECT_TYPE) || ' ' || RTRIM(OWNER) || '.' || OBJECT_NAME OBJECT_NAME,
       DECODE(LMODE,
              0,'NONE',
              1,'NULL',
              2,'ROW-S',
              3,'ROW-X',
              4,'SHARE',
              5,'S/ROW-X',
              6,'EXCLUSIVE',
              'UNKNOWN') LOCKMODE,
       DECODE(REQUEST,
              0,'NONE',
              1,'NULL',
              2,'ROW-S',
              3,'ROW-X',
              4,'SHARE',
              5,'S/ROW-X',
              6,'EXCLUSIVE',
              'UNKNOWN') REQUESTMODE,
       CTIME,
       BLOCK B
FROM V$LOCK, ALL_OBJECTS, SYS.V_$SESSION
WHERE V$LOCK.SID > 6
   AND SYS.V_$SESSION.SID = V$LOCK.SID
   AND V$LOCK.ID1 = ALL_OBJECTS.OBJECT_ID;

以DBA角色, 查看当前数据库里锁的情况可以用如下SQL语句：
COL OWNER FOR A12
COL OBJECT_NAME FOR A16
SELECT B.OWNER,B.OBJECT_NAME,L.SESSION_ID,L.LOCKED_MODE
FROM V$LOCKED_OBJECT L, DBA_OBJECTS B
WHERE B.OBJECT_ID=L.OBJECT_ID;

SQL>SELECT T2.USERNAME,T2.SID,T2.SERIAL#,T2.LOGON_TIME FROM V$LOCKED_OBJECT T1,V$SESSION T2 WHERE T1.SESSION_ID=T2.SID ORDER BY T2.LOGON_TIME;


SQL>SELECT SQL_ADDRESS FROM V$SESSION WHERE SID=;


SQL>SELECT * FROM V$SQLTEXT WHERE ADDRESS=;


SQL>SELECT COMMAND_TYPE,PIECE,SQL_TEXT FROM V$SQLTEXT WHERE ADDRESS=(SELECT SQL_ADDRESS FROM V$SESSION A WHERE SID=18);   


SQL>SELECT OBJECT_ID FROM V$LOCKED_OBJECT;


SQL>SELECT OBJECT_NAME,OBJECT_TYPE FROM DBA_OBJECTS WHERE OBJECT_ID='';
如果有长期出现的一列，可能是没有释放的锁。我们可以用下面SQL语句杀掉长期没有释放非正常的锁： SQL>ALTER SYSTEM KILL SESSION 'SID,SERIAL#';

17、查看等待（wait）情况:
SQL>SELECT V$WAITSTAT.CLASS,V$WAITSTAT.COUNT COUNT, SUM(V$SYSSTAT.VALUE) SUM_VALUE FROM V$WAITSTAT,V$SYSSTAT WHERE V$SYSSTAT.NAME IN('DB BLOCK GETS','CONSISTENT GETS') GROUP BY V$WAITSTAT.CLASS,V$WAITSTAT.COUNT;

18、查看sga情况:
SQL>SELECT NAME, BYTES FROM SYS.V_$SGASTAT ORDER BY NAME ASC;

19、查看catched object:
SQL>SELECT OWNER,NAME,DB_LINK,NAMESPACE,TYPE,SHARABLE_MEM,LOADS, EXECUTIONS,LOCKS,PINS,KEPT FROM V$DB_OBJECT_CACHE;

20、查看V$SQLAREA:
SQL>SELECT SQL_TEXT,SHARABLE_MEM,PERSISTENT_MEM,RUNTIME_MEM,SORTS,
VERSION_COUNT,LOADED_VERSIONS,OPEN_VERSIONS,USERS_OPENING,EXECUTIONS,
USERS_EXECUTING,LOADS,FIRST_LOAD_TIME,INVALIDATIONS,PARSE_CALLS,
DISK_READS,BUFFER_GETS,ROWS_PROCESSED FROM V$SQLAREA;

21、查看object分类数量:
SELECT DECODE(O.TYPE#,1,'INDEX',2,'TABLE',3,'CLUSTER',4,'VIEW',5,'SYNONYM',6, 'SEQUENCE','OTHER') OBJECT_TYPE , COUNT(*) QUANTITY FROM SYS.OBJ$ O WHERE O.TYPE# > 1 GROUP BY DECODE(O.TYPE#,1,'INDEX',2,'TABLE',3,'CLUSTER' ,4,'VIEW',5,'SYNONYM',6,'SEQUENCE','OTHER') UNION SELECT 'COLUMN', COUNT(*) FROM SYS.COL$ UNION SELECT 'DB LINK' , COUNT(*) FROM ALL_OBJECTS;

22、有关connection的相关信息:
1）查看有哪些用户连接
SELECT S.OSUSER OS_USER_NAME,DECODE(SIGN(48 - COMMAND),1,TO_CHAR(COMMAND),
'ACTION CODE #' || TO_CHAR(COMMAND))ACTION,P.PROGRAM ORACLE_PROCESS, STATUS SESSION_STATUS,S.TERMINAL TERMINAL,S.PROGRAM PROGRAM, S.USERNAME USER_NAME,S.FIXED_TABLE_SEQUENCE ACTIVITY_METER,''QUERY,0 MEMORY,0 MAX_MEMORY,0 CPU_USAGE,S.SID,S.SERIAL# SERIAL_NUM FROM V$SESSION S,V$PROCESS P WHERE S.PADDR=P.ADDR AND S.TYPE = 'USER' ORDER BY S.USERNAME, S.OSUSER;

2）根据v.sid查看对应连接的资源占用等情况
SELECT N.NAME,V.VALUE,N.CLASS,N.STATISTIC# FROM V$STATNAME N,V$SESSTAT V WHERE V.SID=18 AND V.STATISTIC# = N.STATISTIC# ORDER BY N.CLASS, N.STATISTIC#;

3）根据sid查看对应连接正在运行的sql
SELECT /*+ PUSH_SUBQ */ COMMAND_TYPE,SQL_TEXT,SHARABLE_MEM, PERSISTENT_MEM,RUNTIME_MEM,SORTS,VERSION_COUNT,LOADED_VERSIONS,OPEN_VERSIONS,USERS_OPENING,EXECUTIONS, USERS_EXECUTING,LOADS,FIRST_LOAD_TIME,INVALIDATIONS,PARSE_CALLS,DISK_READS,BUFFER_GETS,ROWS_PROCESSED,SYSDATE START_TIME,SYSDATE FINISH_TIME,'>'|| ADDRESS SQL_ADDRESS, 'N' STATUS FROM V$SQLAREA WHERE ADDRESS = (SELECT SQL_ADDRESS FROM V$SESSION WHERE SID=8);

根据pid查看sql语句:

SELECT SQL_TEXT FROM V$SQL WHERE ADDRESS IN (SELECT SQL_ADDRESS FROM V$SESSION WHERE SID IN (SELECT SID FROM V$SESSION WHERE PADDR IN (SELECT ADDR FROM V$PROCESS WHERE SPID=&PID)));