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oracle维护、监控、优化常用sql

oracle维护、监控、优化常用sql
 
1) sql监控 
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SELECT SE.sid, schemaname, SE.serial#, PR.spid, SE.status, SUBSTR(SE.program, 1, 10) PROG, 
   SUBSTR(SE.machine, 1, 10) MACH, 
   SQ.sql_text 
FROM v$session SE, v$sqlarea SQ, v$process PR 
WHERE SE.paddr = PR.ADDR(+) 
   AND SE.sql_address = SQ.address(+) 
   AND schemaname ='KING' 
 
ORDER BY SE.sid 
   
---面查出来的sqlid 
select * from table(dbms_xplan.display_cursor('ddzktdys2nz3w')) 
 
select count(*) from v$session 
 
---查看各个状态的sql 
select se.status,sq.sql_text from v$session se,v$sqlarea sq   where se.sql_address=sq.address(+) 
 
--正在执行的 
 
select a.username, a.sid,b.SQL_TEXT, b.SQL_FULLTEXT 
  from v$session a, v$sqlarea b 
where a.sql_address = b.address 
---执行过的 
select b.SQL_TEXT,b.FIRST_LOAD_TIME,b.SQL_FULLTEXT 
  from v$sqlarea b 
where b.FIRST_LOAD_TIME between '2013-03-01/13:30:47' and 
       '2013-03-01/13:50:47' order by b.FIRST_LOAD_TIME 
--(此方法好处可以查看某一时间段执行过的sql,并且 SQL_FULLTEXT 包含了完整的 sql 语句) 
 
--其他 
select OSUSER,PROGRAM,USERNAME,SCHEMANAME,B.Cpu_Time,STATUS,B.SQL_TEXT 
from V$SESSION A LEFT JOIN V$SQL B ON A.SQL_ADDRESS=B.ADDRESS AND A.SQL_HASH_VALUE=B.HASH_VALUE order by b.cpu_time desc 
 
 
select address, sql_text, piece 
  from v$session, v$sqltext 
where address = sql_address 
-- and machine = < you machine name > 
order by address, piece 
 
---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 ; 
 
---查看占io较大的正在运行的session 
 
SELECT se.sid,se.serial#,pr.SPID,se.username,se.status, 
se.terminal,se.program,se.MODULE,se.sql_address,st.event,st. 
p1text,si.physical_reads, 
si.block_changes FROM v$session se,v$session_wait st, 
v$sess_io si,v$process pr WHERE st.sid=se.sid AND st. 
sid=si.sid AND se.PADDR=pr.ADDR AND se.sid>6 AND st. 
wait_time=0 AND st.event NOT LIKE '%SQL%' ORDER BY physical_reads DESC 
 
-- 
alter system set processes = 400 scope = SPFILE 
show processes PARAMETERS 
----查看实例名 
select instance_name from V$instance 
 
 
2)表空间大小查看 
select 
b.file_name 物理文件名, 
b.tablespace_name 表空间, 
b.bytes/1024/1024 大小M, 
(b.bytes-sum(nvl(a.bytes,0)))/1024/1024 已使用M, 
substr((b.bytes-sum(nvl(a.bytes,0)))/(b.bytes)*100,1,5) 利用率 
from dba_free_space a,dba_data_files b                  
where a.file_id=b.file_id 
group by b.tablespace_name,b.file_name,b.bytes 
order by b.tablespace_name 
 
3)索引查看 删除  
---查询某张表的索引 
select * from user_indexes where TABLE_Name = 'CASE_ACLINE_TEMP' 
select * from user_indexes where TABLE_Name = 'CASE_ACLINE_PARTITION' 
---删除某个索引 
DROP INDEX CASE_ACLINE_PARTITION_IDX 
DROP INDEX FK_CASE_ACLINE_TEM_CASE_ID 
 
-- 索引占用大小 
select a.segment_name,a.tablespace_name,b.table_name,a.bytes/1024/1024 mbytes,a.blocks  
from user_segments a, user_indexes b  
where a.segment_name = b.index_name  
and a.segment_NAME = 'CASE_ACLINE_PARTITION_IDX' --索引  
and a.tablespace_name='TEST_TEMP' --表空间  
and b.table_name = 'CASE_ACLINE_PARTITION' --索引所在表  
order by table_name,a.bytes/1024/1024 desc 
 
---查看分区表索引 
SELECT * FROM USER_IND_PARTITIONS T 
WHERE T.INDEX_NAME='CASE_ACLINE_PARTITION_IDX' 
 
4)连接数查看  修改 
 
--连接数 
select count(*) from v$session 
 
--并发连接数 
Select count(*) from v$session where status='ACTIVE'  
---最大连接 
show parameter processes 
---修改连接数 ,重启生效 
alter system set processes = 400 scope = spfile;
 
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