使用SQL语句监控数据库性能

1、当前数据库各个终端连接数

SELECT "连接数","终端名称"

FROM ( SELECT COUNT(TERMINAL) AS 连接数,

TERMINAL AS 终端名称

FROM v$sessionGROUP BY TERMINAL

)

ORDER BY 连接数 DESC;

2、查询性能最差的SQL

SELECTdisk_reads,executions,rows_processed,

first_load_time,sql_text

FROMsys.v_$sqlarea

WHEREdisk_reads >10

AND executions

ORDER BYfirst_load_time;

3、找使用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;

4、当前各用户运行什么SQL语句

SELECTosuser, username, sql_text

FROMv$session a, v$sqltext b

WHEREa.sql_address =b.address

ORDER BY address, piece;