SQL语句大全―查看表空间

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�a生EXPLAIN PLAN¡�z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)