oracle数据库性能监控的常用的SQL
oracle数据库性能监控的SQL
1. 监控事例的等待
SQL> 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
SQL> 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
SQL> 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
SQL> 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
SQL> 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
SQL> 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
SQL> 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%
SQL> SELECT SUM(PINS) "TOTAL PINS", SUM(RELOADS) "TOTAL RELOADS",
SUM(RELOADS)/SUM(PINS) *100 LIBCACHE FROM V$LIBRARYCACHE;

SQL> 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
SQL> 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%
SQL> 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
SQL> 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
SQL> 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
SQL>SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE;
SQL>SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE;
SQL>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)
SQL>SELECT SUM(GETS) "DIC