oracle管理常用SQL语句

参考博客：

http://panhongbin100.iteye.com/blog/1596414

https://blog.csdn.net/z69183787/article/details/18841621

-----------------------------数据库连接数相关-------------------------------

--数据库允许的最大连接数
select value from v$parameter where name ='processes';   

--当前的进程数
select count(*) from v$process;    

--当前的连接数,两个参数间的关系：sessions=1.1*processes+5            
select count(*) from v$session;     
              
--并发连接数
select count(*) from v$session where status='ACTIVE';　

--其中sessions_highwater是记录曾经到达的最大会话数
select * from v$parameter where name LIKE 'proc%'; 

---------------------------表空间相关----------------------------------------

--表空间使用率
SELECT a.tablespace_name "表空间名", total "表空间大小", free "表空间剩余大小",  
     (total - free) "表空间使用大小", total / (1024 * 1024 * 1024) "表空间大小(G)",  
      free / (1024 * 1024 * 1024) "表空间剩余大小(G)",  
     (total - free) / (1024 * 1024 * 1024) "表空间使用大小(G)",  
       round((total - free) / total, 4) * 100 "使用率 %" FROM (SELECT tablespace_name,   
     SUM(bytes) free 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;  

--表空间的文件路径,是否自动扩展
select tablespace_name, file_id,file_name,AUTOEXTENSIBLE ,
       round(bytes/(1024*1024),0) total_space from dba_data_files
       order by tablespace_name;

--修改数据文件大小
alter database datafile '/oraDatas/GMAMP796.dbf' resize 1024m; 

--给表空间增加数据文件
ALTER TABLESPACE dataspace ADD DATAFILE   
      '/data/oradata/data/tablespace_dataspace/dataspace_6.dbf' SIZE 30G AUTOEXTEND ON NEXT 50M;  

--查看表空间占用磁盘情况   
SELECT B.FILE_ID 文件ID号,   
       B.TABLESPACE_NAME 表空间名,   
       B.BYTES/1024/1024 "total(M)",   
       (B.BYTES - SUM(NVL(A.BYTES, 0))/1024/1024) "used(M)",   
       SUM(NVL(A.BYTES, 0)/1024/1024) "free(M)",   
       round(SUM(NVL(A.BYTES, 0)) / (B.BYTES) * 100,2) 剩余百分比   
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;   

-------------------服务名与实例名---------------------------------------------

--查看数据库的服务名
select name from v$database ;    

--查看数据库的实例名   
select * from v$instance;

-----------------错误信息--------------------------------------------------------

--查看错误信息
select * from user_errors;   

--------------SGA信息------------------------------------------------------------

--查看SGA
select * from v$sga;

--查看share pool，large pool，java pool等信息
select component, (current_size/1024/1024) "当前大小(M)",
(min_size/1024/1024) "最小值(M)",(max_size/1024/1024) "最大值(M)" from v$sga_dynamic_components;
select * from v$sga_dynamic_components;

--监控sga内存分配信息
select * from v$sgainfo;  

--监控每个用户的磁盘io及io命中率

--监控每个用户的磁盘io及io命中率
    select v$sess_io.*,(block_gets+consistent_gets) reads,  
    ((block_gets+consistent_gets-physical_reads)/(block_gets+consistent_gets)) ratio  
    from v$sess_io  
    where (block_gets+consistent_gets)>=1000  
    order by (block_gets+consistent_gets) desc;  

--查询当前正在执行的sql及io信息

--查询当前正在执行的sql及io信息
    select a.sql_text,  
    a.sql_fulltext,  
    a.cpu_time,  
    b.sid,  
    b.serial#,  
    b.username,  
    b.machine,  
    b.terminal,  
    b.program,  
    c.block_gets,  
    c.consistent_gets,  
    c.physical_reads,  
    c.block_changes,  
    c.consistent_changes  
    from v$sql a,  
    v$session b,  
    v$sess_io c  
    where a.address=b.sql_address  
    and b.sid=c.sid  
    order by c.block_changes desc; 

--查询刚执行过的sql和io信息

--查询刚执行过的sql和io信息
    select a.sql_text,  
    a.sql_fulltext,  
    a.cpu_time,  
    b.sid,  
    b.serial#,  
    b.username,  
    b.machine,  
    b.terminal,  
    b.program,  
    c.block_gets,  
    c.consistent_gets,  
    c.physical_reads,  
    c.block_changes,  
    c.consistent_changes  
    from v$sql a,  
    v$session b,  
    v$sess_io c  
    where a.address=b.prev_sql_addr  
    and b.sid=c.sid  
    order by c.block_changes desc;  

--监控SGA命中率  

--监控SGA命中率   
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;   

--性能最差的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 < 100;   

--查询使用CPU多的用户session   

SELECT A.SID,   
       SPID,   
       STATUS,   
       SUBSTR(A.PROGRAM, 1, 40) PROG,   
       A.TERMINAL,   
       OSUSER,   
       VALUE / 60 / 100 VALUE   
  FROM V$SESSION A, V$PROCESS B, V$SESSTAT C   
 WHERE C.STATISTIC# = 12   
   AND C.SID = A.SID   
   AND A.PADDR = B.ADDR   
 ORDER BY VALUE DESC;   

 --当前每个会话使用的对象数

--当前每个会话使用的对象数   
SELECT A.SID, S.TERMINAL, S.PROGRAM, COUNT(A.SID)   
FROM V$ACCESS A, V$SESSION S   
WHERE A.OWNER <> 'SYS'  
     AND S.SID = A.SID   
GROUP BY A.SID, S.TERMINAL, S.PROGRAM   
ORDER BY COUNT(A.SID);  

--内存命中率

--内存命中率
SELECT name profile,cnt,decode( total, 0, 0, round( cnt * 100 / total)) "内存命中率"
FROM ( SELECT name, value cnt, ( SUM( value ) OVER()) total
FROM v$sysstat
WHERE name LIKE 'workarea exec%');

-- 数据缓冲区高速缓存

-- 数据缓冲区高速缓存
SELECT physical_reads, db_block_gets, consistent_gets, NAME,
100 * ( 1 - ( physical_reads / (consistent_gets + db_block_gets - physical_reads))) "Data Buffer Hit Ratio"
FROM v$buffer_pool_statistics;

-- 重做日至缓冲区

-- 重做日至缓冲区
SELECT a.VALUE redo_entries, b.VALUE redo_buffer_allocation_retries,
ROUND ((1 - b.VALUE / a.VALUE) * 100, 4) log_buffer_ratio
FROM v$sysstat a, v$sysstat b
WHERE a.NAME = 'redo entries' AND b.NAME = 'redo buffer allocation retries';

-- 数据字典高速缓存

SELECT SUM (pinhits) / SUM (pins) * 100 "hit radio"
FROM v$librarycache;

--执行次数最多的top 10

--执行次数最多的top 10
select sql_text,executions
from (select sql_text,executions,
rank() over
(order by executions desc) exec_rank
from v$sql)
where exec_rank <=10;