1. 監控事例的等待 select event,sum(decode(wait_Time,0,0,1)) 'Prev', sum(decode(wait_Time,0,1,0)) 'Curr',count(*) 'Tot' from v$session_Wait group by event order by 4; 2. 回滾段的爭用情況 select name, waits, gets, waits/gets 'Ratio' from v$rollstat a, v$rollname b where a.usn = b.usn; 3. 監控表空間的 I/O 比例 select df.tablespace_name name,df.file_name 'file',f.phyrds pyr, f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw from v$filestat f, dba_data_files df where f.file# = df.file_id order by df.tablespace_name; 4. 監控文件系統的 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.在某個用戶下找所有的索引 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. 監控 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$sysstat c where a.statistic# = 38 and b.statistic# = 39 and c.statistic# = 40; 7. 監控 SGA 中字典緩沖區的命中率 select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 'miss ratio', (1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 'Hit ratio' from v$rowcache where gets+getmisses <>;0 group by parameter, gets, getmisses; 8. 監控 SGA 中共享緩存區的命中率，應該小于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. 顯示所有數據庫對象的類別和大小 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. 監控 SGA 中重做日志緩存區的命中率，應該小于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$latch WHERE name IN ('redo allocation', 'redo copy'); 11. 監控內存和硬盤的排序比率，最好使它小于 .10，增加 sort_area_size SELECT name, value FROM v$sysstat WHERE name IN ('sorts (memory)', 'sorts (disk)'); 12. 監控當前數據庫誰在運行什么SQL語句 SELECT osuser, username, sql_text from v$session a, v$sqltext b where a.sql_address =b.address order by address, piece; 13. 監控字典緩沖區 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$LIBRARYCACHE; 后者除以前者,此比率小于1%,接近0%為好。 14. 找Oracle字符集 select * from sys.props$ where name='NLS_CHARACTERSET'; 15. 監控 MTS select busy/(busy+idle) 'shared servers busy' from v$dispatcher; 此值大于0.5時，參數需加大 select sum(wait)/sum(totalq) 'dispatcher waits' from v$queue where type='dispatcher'; select count(*) from v$dispatcher; select servers_highwater from v$mts; servers_highwater接近mts_max_servers時，參數需加大 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、索引的存儲情況檢查 select segment_name,sum(bytes),count(*) ext_quan from dba_extents where tablespace_name='&tablespace_name' and segment_type='TABLE' group by tablespace_name,segment_name; select segment_name,count(*) from dba_extents where segment_type='INDEX' and owner='&owner' group by segment_name; 18、找使用CPU多的用戶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;