查询v$session_longops动态
性能视图可以查看运行时间大于6秒的查询，如果想让运行时间大于6秒的查询被
数据库引擎收集，必须满足以下条件：1 参数timed_statistics或sql_trace为true
2 涉及的对象（表或索引）必须被分析（analyze或dbms_stats）
监控
数据库性能的SQL
[Ref:
http://xzh2000.itpub.net/post/96/102574 ]
在v$session_longops视图中，sofar字段表示已经扫描的块数，totalwork表示总得需要扫描的块数，所以我们即可以对正在运行的长查询进行监控，比如在索引创建时，查看索引创建的进度，也可以查看系统中以往的长查询。。。
col opname format a32
col target_desc format a32
col perwork format a12
set lines 131
select sid,OPNAME,TARGET_DESC,sofar,TOTALWORK,trunc(sofar/totalwork*100,2)||'%' as perwork
from v$session_longops where sofar!=totalwork;
set lines 121
set pages 999
col opname format a29
col target format a29
col target_desc format a12
col perwork format a12
col remain format 99
col start_time format a21
col sofar format 99999999
col totalwork format 99999999
col sql_text format a101
col bufgets format 99999999
select opname,target,to_char(start_time,'yy-mm-dd:hh24:mi:ss') start_time,elapsed_seconds elapsed,
executions execs,buffer_gets/decode(executions,0,1,executions) bufgets,module,sql_text
from v$session_longops sl,v$sqlarea sa
where sl.sql_hash_value = sa.hash_value and upper(substr(module,1,4)) <> 'RMAN' and substr(opname,1,4) <> 'RMAN'
and module <> 'SQL*Plus' and sl.start_time>trunc(sysdate)
order by start_time;
==========================================================
1. 监控事例的等待 select event,sum(decode(wait_Time,0,0,1)) "
rev", sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot" from v$session_Wait group by event order by 4;
2. 回滚段的争用情况 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 select df.tablespace_name name,df.file_name "file",f.phyrds pyr, f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw from v$filestat f, dba_data_files df where f.file# = df.file_id order by df.tablespace_name;
4. 监控
文件系统的 I/O 比例 select substr(a.file#,1,2) "#", substr(a.name,1,30) "Name", a.status, a.bytes, b.phyrds, b.phywrts from v$datafile a, v$filestat b where a.file# = b.file#;
5.在某个用户下找所有的索引 select user_indexes.table_name, user_indexes.index_name,uniqueness, column_name from user_ind_columns, user_indexes where user_ind_columns.index_name = user_indexes.index_name and user_ind_columns.table_name = user_indexes.table_name order by user_indexes.table_type, user_indexes.table_name, user_indexes.index_name, column_position;
6. 监控 SGA 的命中率 select a.value + b.value "logical_reads", c.value "phys_reads", round(100 * ((a.value+b.value)-c.value) / (a.value+b.value)) "BUFFER HIT RATIO" from v$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 select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio", (1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio" from v$rowcache where gets+getmisses <>0 group by parameter, gets, getmisses;
8. 监控 SGA 中共享缓存区的命中率，应该小于1% select sum(pins) "Total Pins", sum(reloads) "Total Reloads", sum(reloads)/sum(pins) *100 libcache from v$librarycache; select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent" from v$librarycache;
9. 显示所有数据库对象的类别和大小 select count(name) num_instances ,type ,sum(source_size) source_size , sum(parsed_size) parsed_size ,sum(code_size) code_size ,sum(error_size) error_size, sum(source_size) +sum(parsed_size) +sum(code_size) +sum(error_size) size_required from dba_object_size group by type order by 2;
10. 监控 SGA 中重做日志缓存区的命中率，应该小于1% SELECT name, gets, misses, immediate_gets, immediate_misses, Decode(gets,0,0,misses/gets*100) ratio1, Decode(immediate_gets+immediate_misses,0,0, immediate_misses/(immediate_gets+immediate_misses)*100) ratio2 FROM v$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 .
11，增加 sort_area_size SELECT name, value FROM v$sysstat WHERE name IN ('sorts (memory)', 'sorts (disk)');
12. 监控当前数据库谁在运行什么SQL语句 SELECT osuser, username, sql_text from v$session a, v$sqltext b where a.sql_address =b.address order by address, piece;
13. 监控字典缓冲区 SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE; SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE; SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM V$LIBRARYCACHE; 后者除以前者,此比率小于1%,接近0%为好。 SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES" FROM V$ROWCACHE
14. 找
ORACLE字符集 select * from sys.props$ where name='NLS_CHARACTERSET';
15. 监控 MTS select busy/(busy+idle) "shared servers busy" from v$dispatcher; 此值大于0.5时，参数需加大 select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where type='dispatcher'; select count(*) from v$dispatcher; select servers_highwater from v$mts; servers_highwater接近mts_max_servers时，参数需加大
16. 碎片程度 select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name having count(tablespace_name)>10; alter tablespace name coalesce; alter table name deallocate unused; create or replace view ts_blocks_v as select tablespace_name,block_id,bytes,blocks,'free space' segment_name from dba_free_space union all select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents; select * from ts_blocks_v; select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space group by tablespace_name;
查看碎片程度高的表 SELECT segment_name table_name , COUNT(*) extents FROM dba_segments WHERE owner NOT IN ('SYS', 'SYSTEM') GROUP BY segment_name HAVING COUNT(*) = (SELECT MAX( COUNT(*) ) FROM dba_segments GROUP BY segment_name);
17. 表、索引的
存储情况检查 select segment_name,sum(bytes),count(*) ext_quan from dba_extents where
