Oracle日常性能查看

判断回滚段竞争的SQL语句：（当Ratio大于2时存在回滚段竞争，需要增加更多的回滚段）select rn.name, rs.GETS, rs.WAITS, (rs.WAITS / rs.GETS) * 100 ratiofrom v$rollstat rs, v$rollname rnwhere rs.USN = rn.usn 判断恢复日志竞争的SQL语句：（immediate_contention或wait_contention的值大于1时存在竞争）select name,(t.IMMEDIATE_MISSES /decode((t.IMMEDIATE_GETS t.IMMEDIATE_MISSES),0,-1,(t.IMMEDIATE_GETS t.IMMEDIATE_MISSES))) * 100 immediate_contention,(t.MISSES / decode((t.GETS t.MISSES), 0, -1, (t.GETS t.MISSES))) * 100 wait_contentionfrom v$latch twhere name in ('redo copy', 'redo allocation')判断表空间碎片：（如果最大空闲空间占总空间很大比例则可能不存在碎片，如果比例较小，且有许多空闲空间，则可能碎片很多）select t.tablespace_name,sum(t.bytes),max(t.bytes),count(*),max(t.bytes) / sum(t.bytes) radiofrom dba_free_space tgroup by t.tablespace_nameorder by t.tablespace_name确定命中排序域的次数：select t.NAME, t.VALUE from v$sysstat t where t.NAME like 'sort%'查看当前SGA值：select * from v$sga确定高速缓冲区命中率：（如果命中率低于70％，则应该加大init.ora参数中的DB_BLOCK_BUFFER的值）select 1 - sum(decode(name, 'physical reads', value, 0)) /(sum(decode(name, 'db block gets', value, 0)) sum(decode(name, 'consistent gets', value, 0))) hit_ratiofrom v$sysstat twhere name in ('physical reads', 'db block gets', 'consistent gets')确定共享池中的命中率：（如果ratio1大于1时，需要加大共享池，如果ratio2大于10％时，需要加大共享池SHARED_POOL_SIZE）select sum(pins) pins,sum(reloads) reloads,(sum(reloads) / sum(pins)) * 100 ratio1from v$librarycacheselect sum(gets) gets,sum(getmisses) getmisses,(sum(getmisses) / sum(gets)) * 100 ratio2from v$rowcache查询INIT.ORA参数：select * from v$parameter/////Oracle性能参数查看（转）0、数据库参数属性col PROPERTY_NAME format a25col PROPERTY_VALUE format a30col DESCRIPTION format a100select * from database_properties;select * from v$version;1、求当前会话的SID，SERIAL#SELECT Sid, Serial# FROM V$sessionWHERE Audsid = Sys_Context('USERENV', 'SESSIONID');2、查询session的OS进程IDSELECT p.Spid "OS Thread", b.NAME "Name-User", s.Program, s.Sid, s.Serial#,s.Osuser, s.MachineFROM V$process p, V$session s, V$bgprocess bWHERE p.Addr = s.PaddrAND p.Addr = b.Paddr And (s.sid=&1 or p.spid=&1)UNION ALLSELECT p.Spid "OS Thread", s.Username "Name-User", s.Program, s.Sid,s.Serial#, s.Osuser, s.MachineFROM V$process p, V$session sWHERE p.Addr = s.PaddrAnd (s.sid=&1 or p.spid=&1)AND s.Username IS NOT NULL;3、根据sid查看对应连接正在运行的sql SELECT /* PUSH_SUBQ */ Command_Type, Sql_Text, Sharable_Mem, Persistent_Mem, Runtime_Mem, Sorts,Version_Count, Loaded_Versions, Open_Versions, Users_Opening, Executions,Users_Executing, Loads, First_Load_Time, Invalidations, Parse_Calls,Disk_Reads, Buffer_Gets, Rows_Processed, SYSDATE Start_Time,SYSDATE Finish_Time, '>' || Address Sql_Address, 'N' StatusFROM V$sqlarea WHERE Address = (SELECT Sql_AddressFROM V$session WHERE Sid = &sid );4、查找object为哪些进程所用SELECT p.Spid, s.Sid, s.Serial# Serial_Num, s.Username User_Name,a.TYPE Object_Type, s.Osuser Os_User_Name, a.Owner,a.OBJECT Object_Name,Decode(Sign(48 - Command), 1, To_Char(Command), 'Action Code #' || To_Char(Command)) Action,p.Program Oracle_Process, s.Terminal Terminal, s.Program Program,s.Status Session_StatusFROM V$session s, V$access a, V$process pWHERE s.Paddr = p.AddrAND s.TYPE = 'USER'AND a.Sid = s.SidAND a.OBJECT = '&obj'ORDER BY s.Username, s.Osuser5、查看有哪些用户连接SELECT s.Osuser Os_User_Name,Decode(Sign(48 - Command),1,To_Char(Command),'Action Code #' || To_Char(Command)) Action,p.Program Oracle_Process, Status Session_Status, s.Terminal Terminal,s.Program Program, s.Username User_Name,s.Fixed_Table_Sequence Activity_Meter, '' Query, 0 Memory,0 Max_Memory, 0 Cpu_Usage, s.Sid, s.Serial# Serial_NumFROM V$session s, V$process pWHERE s.Paddr = p.AddrAND s.TYPE = 'USER'ORDER BY s.Username, s.Osuser6、根据v.sid查看对应连接的资源占用等情况SELECT n.NAME, v.VALUE, n.CLASS, n.Statistic# FROM V$statname n, V$sesstat vWHERE v.Sid = &sidAND v.Statistic# = n.Statistic#ORDER BY n.CLASS, n.Statistic#7、查询耗资源的进程（top session）SELECT s.Schemaname Schema_Name,Decode(Sign(48 - Command),1, To_Char(Command), 'Action Code #' || To_Char(Command)) Action,Status Session_Status, s.Osuser Os_User_Name, s.Sid, p.Spid,s.Serial# Serial_Num, Nvl(s.Username, '[Oracle process]') User_Name,s.Terminal Terminal, s.Program Program, St.VALUE Criteria_ValueFROM V$sesstat St, V$session s, V$process pWHERE St.Sid = s.SidAND St.Statistic# = To_Number('38')AND ('ALL' = 'ALL' OR s.Status = 'ALL')AND p.Addr = s.PaddrORDER BY St.VALUE DESC, p.Spid ASC, s.Username ASC, s.Osuser ASC8、查看锁（lock）情况SELECT /* RULE */ Ls.Osuser Os_User_Name, Ls.Username User_Name,Decode(Ls.TYPE,'RW', 'Row wait enqueue lock', 'TM', 'DML enqueue lock','TX', 'Transaction enqueue lock', 'UL', 'User supplied lock') Lock_Type,o.Object_Name OBJECT,Decode(Ls.Lmode,1, NULL, 2, 'Row Share', 3, 'Row Exclusive',4, 'Share', 5, 'Share Row Exclusive', 6, 'Exclusive',NULL) Lock_Mode,o.Owner, Ls.Sid, Ls.Serial# Serial_Num, Ls.Id1, Ls.Id2 FROM Sys.Dba_Objects o, (SELECT s.Osuser, s.Username, l.TYPE, l.Lmode, s.Sid, s.Serial#, l.Id1,l.Id2 FROM V$session s, V$lock lWHERE s.Sid = l.Sid) LsWHERE o.Object_Id = Ls.Id1AND o.Owner <> 'SYS'ORDER BY o.Owner, o.Object_Name;9、查看等待（wait）情况SELECT Ws.CLASS, Ws.COUNT COUNT, SUM(Ss.VALUE) Sum_ValueFROM V$waitstat Ws, V$sysstat SsWHERE Ss.NAME IN ('db block gets', 'consistent gets')GROUP BY Ws.CLASS, Ws.COUNT;10、求process/session的状态SELECT p.Pid, p.Spid, s.Program, s.Sid, s.Serial#FROM V$process p, V$session sWHERE s.Paddr = p.Addr;11、求谁阻塞了某个session(10g)SELECT Sid, Username, Event, Blocking_Session, Seconds_In_Wait, Wait_TimeFROM V$sessionWHERE State IN ('WAITING')AND Wait_Class != 'Idle';12、查会话的阻塞col user_name format a32SELECT /* rule */ Lpad(' ', Decode(l.Xidusn, 0, 3, 0)) || l.Oracle_Username User_Name,o.Owner, o.Object_Name, s.Sid, s.Serial#FROM V$locked_Object l, Dba_Objects o, V$session sWHERE l.Object_Id = o.Object_IdAND l.Session_Id = s.SidORDER BY o.Object_Id, Xidusn DESC;col username format a15col lock_level format a8col owner format a18col object_name format a32SELECT /* rule */ s.Username,Decode(l.TYPE, 'tm', 'table lock', 'tx', 'row lock', NULL) Lock_Level,o.Owner, o.Object_Name, s.Sid, s.Serial#FROM V$session s, V$lock l, Dba_Objects oWHERE l.Sid = s.SidAND l.Id1 = o.Object_Id( )AND s.Username IS NOT NULL;13、求等待的事件及会话信息/求会话的等待及会话信息SELECT Se.Sid, s.Username, Se.Event, Se.Total_Waits, Se.Time_Waited,Se.Average_WaitFROM V$session s, V$session_Event SeWHERE s.Username IS NOT NULLAND Se.Sid = s.SidAND s.Status = 'ACTIVE'AND Se.Event NOT LIKE '%SQL*Net%'ORDER BY s.Username;SELECT s.Sid, s.Username, Sw.Event, Sw.Wait_Time, Sw.State,Sw.Seconds_In_WaitFROM V$session s, V$session_Wait SwWHERE s.Username IS NOT NULLAND Sw.Sid = s.SidAND Sw.Event NOT LIKE '%SQL*Net%'ORDER BY s.Username;14、求会话等待的file_id/block_idcol event format a24col p1text format a12col p2text format a12col p3text format a12SELECT Sid, Event, P1text, P1, P2text, P2, P3text, P3FROM V$session_WaitWHERE Event NOT LIKE '%SQL%'AND Event NOT LIKE '%rdbms%'AND Event NOT LIKE '%mon%'ORDER BY Event;SELECT NAME, Wait_TimeFROM V$latch lWHERE EXISTS (SELECT 1FROM (SELECT Sid, Event, P1text, P1, P2text, P2, P3text, P3FROM V$session_WaitWHERE Event NOT LIKE '%SQL%'AND Event NOT LIKE '%rdbms%'AND Event NOT LIKE '%mon%') xWHERE x.P1 = l.Latch#);15、求会话等待的对象col owner format a18col segment_name format a32col segment_type format a32SELECT Owner, Segment_Name, Segment_TypeFROM Dba_ExtentsWHERE File_Id = &File_IdAND &Block_Id BETWEEN Block_Id AND Block_Id Blocks - 1;16、求出某个进程，并对它进行跟踪SELECT s.Sid, s.Serial#FROM V$session s, V$process pWHERE s.Paddr = p.AddrAND p.Spid = &1;Exec Dbms_System.Set_Sql_Trace_In_Session(&1, &2, TRUE);Exec Dbms_System.Set_Sql_Trace_In_Session(&1, &2, FALSE);17、求当前session的跟踪文件SELECT P1.VALUE || '/' || P2.VALUE || '_ora_' || p.Spid || '.ora' FilenameFROM V$process p, V$session s, V$parameter P1, V$parameter P2WHERE P1.NAME = 'user_dump_dest'AND P2.NAME = 'instance_name'AND p.Addr = s.PaddrAND s.Audsid = Userenv('SESSIONID')AND p.Background IS NULLAND Instr(p.Program, 'CJQ') = 0;18、求出锁定的对象SELECT Do.Object_Name, Session_Id, Process, Locked_ModeFROM V$locked_Object Lo, Dba_Objects DoWHERE Lo.Object_Id = Do.Object_Id;19、DB_Cache建议SELECT size_for_estimate, buffers_for_estimate, estd_physical_read_factor, estd_physical_readsFROM V$DB_CACHE_ADVICEWHERE name = 'DEFAULT'AND block_size = (SELECT value FROM V$PARAMETER WHERE name = 'db_block_size')AND advice_status = 'ON';20、查看各项SGA相关参数：SGA，SGASTATselect substr(name,1,10) name,substr(value,1,10) value from v$parameter where name = 'log_buffer';select * from v$sgastat ;select * from v$sga;show parameters area_size   #查看 各项区域内存参数， 其中sort_area为排序参数用； 各项视图建议参数值：V$DB_CACHE_ADVICE、V$SHARED_POOL_ADVICE），关于PGA也有相关视图V$PGA_TARGET_ADVICE 等。21、内存使用锁定在物理内存：AIX 5L（AIX 4.3.3 以上）logon aix as rootcd /usr/samples/kernel./vmtune (信息如下) v_pingshm已经是1./vmtune -S 1然后oracle用户修改initSID.ora 中 lock_sga = true重新启动数据库HP UNIXRoot身份登陆Create the file "/etc/privgroup": vi /etc/privgroupAdd line "dba MLOCK" to fileAs root, run the command "/etc/setprivgrp -f /etc/privgroup":$/etc/setprivgrp -f /etc/privgrouporacle用户修改initSID.ora中lock_sga=true重新启动数据库SOLARIS (solaris2.6以上)8i版本以上数据库默认使用隐藏参数 use_ism = true ，自动锁定SGA于内存中,不用设置lock_sga, 如果设置 lock_sga =true 使用非 root 用户启动数据库将返回错误。WINDOWS （作用不大）不能设置lock_sga=true,可以通过设置pre_page_sga=true,使得数据库启动的时候就把所有内存页装载，这样可能起到一定的作用。22、内存参数调整数据缓冲区命中率select value from v$sysstat where name ='physical reads';select value from v$sysstat where name ='physical reads direct';select value from v$sysstat where name ='physical reads direct (lob)';select value from v$sysstat where name ='consistent gets';select value from v$sysstat where name = 'db block gets';这里命中率的计算应该是令 x = physical reads direct physical reads direct (lob)命中率 =100 - ( physical reads - x) / (consistent gets db block gets - x)*100通常如果发现命中率低于90%,则应该调整应用可可以考虑是否增大数据缓冲区；共享池的命中率select sum(pinhits)/sum(pins)*100 "hit radio" from v$librarycache;假如共享池的命中率低于95%,就要考虑调整应用（通常是没使用bind var ）或者增加内存；关于排序部分select name,value from v$sysstat where name like '%sort%';假如我们发现sorts (disk)/ (sorts (memory) sorts (disk))的比例过高，则通常意味着sort_area_size 部分内存较小，可考虑调整相应的参数。关于log_bufferselect name,value from v$sysstatwhere name in('redo entries','redo buffer allocation retries');假如 redo buffer allocation retries/ redo entries 的比例超过1%我们就可以考虑增大log_buffer /////July 28oracle 常用SQL查询，望对大家有所启示1、查看表空间的名称及大小select t.tablespace_name, round(sum(bytes/(1024*1024)),0) ts_sizefrom dba_tablespaces t, dba_data_files dwhere t.tablespace_name = d.tablespace_namegroup by t.tablespace_name;2、查看表空间物理文件的名称及大小select tablespace_name, file_id, file_name,round(bytes/(1024*1024),0) total_spacefrom dba_data_filesorder by tablespace_name;3、查看回滚段名称及大小select segment_name, tablespace_name, r.status,(initial_extent/1024) InitialExtent,(next_extent/1024) NextExtent,max_extents, v.curext CurExtentFrom dba_rollback_segs r, v$rollstat vWhere r.segment_id = v.usn( )order by segment_name ;4、查看控制文件select name from v$controlfile;5、查看日志文件select member from v$logfile;6、查看表空间的使用情况select sum(bytes)/(1024*1024) as free_space,tablespace_namefrom dba_free_spacegroup by tablespace_name;SELECT A.TABLESPACE_NAME,A.BYTES TOTAL,B.BYTES USED, C.BYTES FREE,(B.BYTES*100)/A.BYTES "% USED",(C.BYTES*100)/A.BYTES "% FREE"FROM SYS.SM$TS_AVAIL A,SYS.SM$TS_USED B,SYS.SM$TS_FREE CWHERE A.TABLESPACE_NAME=B.TABLESPACE_NAME AND A.TABLESPACE_NAME=C.TABLESPACE_NAME;7、查看数据库库对象select owner, object_type, status, count(*) count# from all_objects group by owner, object_type, status;8、查看数据库的版本　Select version FROM Product_component_versionWhere SUBSTR(PRODUCT,1,6)='Oracle';9、查看数据库的创建日期和归档方式Select Created, Log_Mode, Log_Mode From V$Database;10、捕捉运行很久的SQLcolumn username format a12column opname format a16column progress format a8select username,sid,opname,round(sofar*100 / totalwork,0) || '%' as progress,time_remaining,sql_textfrom v$session_longops , v$sqlwhere time_remaining <> 0and sql_address = addressand sql_hash_value = hash_value/11。查看数据表的参数信息SELECT partition_name, high_value, high_value_length, tablespace_name,pct_free, pct_used, ini_trans, max_trans, initial_extent,next_extent, min_extent, max_extent, pct_increase, FREELISTS,freelist_groups, LOGGING, BUFFER_POOL, num_rows, blocks,empty_blocks, avg_space, chain_cnt, avg_row_len, sample_size,last_analyzedFROM dba_tab_partitions--WHERE table_name = :tname AND table_owner = :townerORDER BY partition_position12.查看还没提交的事务select * from v$locked_object;select * from v$transaction;13。查找object为哪些进程所用selectp.spid,s.sid,s.serial# serial_num,s.username user_name,a.type object_type,s.osuser os_user_name,a.owner,a.object object_name,decode(sign(48 - command),1,to_char(command), 'Action Code #' || to_char(command) ) action,p.program oracle_process,s.terminal terminal,s.program program,s.status session_statusfrom v$session s, v$access a, v$process pwhere s.paddr = p.addr ands.type = 'USER' anda.sid = s.sid anda.object='SUBSCRIBER_ATTR'order by s.username, s.osuser14。回滚段查看select rownum, sys.dba_rollback_segs.segment_name Name, v$rollstat.extentsExtents, v$rollstat.rssize Size_in_Bytes, v$rollstat.xacts XActs,v$rollstat.gets Gets, v$rollstat.waits Waits, v$rollstat.writes Writes,sys.dba_rollback_segs.status status from v$rollstat, sys.dba_rollback_segs,v$rollname where v$rollname.name( ) = sys.dba_rollback_segs.segment_name andv$rollstat.usn ( ) = v$rollname.usn order by rownum15。耗资源的进程（top session）select s.schemaname schema_name, decode(sign(48 - command), 1,to_char(command), 'Action Code #' || to_char(command) ) action, statussession_status, s.osuser os_user_name, s.sid, p.spid , s.serial# serial_num,nvl(s.username, '[Oracle process]') user_name, s.terminal terminal,s.program program, st.value criteria_value from v$sesstat st, v$session s , v$process pwhere st.sid = s.sid and st.statistic# = to_number('38') and ('ALL' = 'ALL'or s.status = 'ALL') and p.addr = s.paddr order by st.value desc, p.spid asc, s.username asc, s.osuser asc16。查看锁（lock）情况select /* RULE */ ls.osuser os_user_name, ls.username user_name,decode(ls.type, 'RW', 'Row wait enqueue lock', 'TM', 'DML enqueue lock', 'TX','Transaction enqueue lock', 'UL', 'User supplied lock') lock_type,o.object_name object, decode(ls.lmode, 1, null, 2, 'Row Share', 3,'Row Exclusive', 4, 'Share', 5, 'Share Row Exclusive', 6, 'Exclusive', null)lock_mode, o.owner, ls.sid, ls.serial# serial_num, ls.id1, ls.id2from sys.dba_objects o, ( select s.osuser, s.username, l.type,l.lmode, s.sid, s.serial#, l.id1, l.id2 from v$session s,v$lock l where s.sid = l.sid ) ls where o.object_id = ls.id1 and o.owner<> 'SYS' order by o.owner, o.object_name17。查看等待（wait）情况SELECT v$waitstat.class, v$waitstat.count count, SUM(v$sysstat.value) sum_valueFROM v$waitstat, v$sysstat WHERE v$sysstat.name IN ('db block gets','consistent gets') group by v$waitstat.class, v$waitstat.count18。查看sga情况SELECT NAME, BYTES FROM SYS.V_$SGASTAT ORDER BY NAME ASC19。查看catched objectSELECT owner, name, db_link, namespace,type, sharable_mem, loads, executions,locks, pins, kept FROM v$db_object_cache20。查看V$SQLAREASELECT SQL_TEXT, SHARABLE_MEM, PERSISTENT_MEM, RUNTIME_MEM, SORTS,VERSION_COUNT, LOADED_VERSIONS, OPEN_VERSIONS, USERS_OPENING, EXECUTIONS,USERS_EXECUTING, LOADS, FIRST_LOAD_TIME, INVALIDATIONS, PARSE_CALLS, DISK_READS,BUFFER_GETS, ROWS_PROCESSED FROM V$SQLAREA21。查看object分类数量select decode (o.type#,1,'INDEX' , 2,'TABLE' , 3 , 'CLUSTER' , 4, 'VIEW' , 5 ,'SYNONYM' , 6 , 'SEQUENCE' , 'OTHER' ) object_type , count(*) quantity fromsys.obj$ o where o.type# > 1 group by decode (o.type#,1,'INDEX' , 2,'TABLE' , 3, 'CLUSTER' , 4, 'VIEW' , 5 , 'SYNONYM' , 6 , 'SEQUENCE' , 'OTHER' ) union select'COLUMN' , count(*) from sys.col$ union select 'DB LINK' , count(*) from22。按用户查看object种类select u.name schema, sum(decode(o.type#, 1, 1, NULL)) indexes,sum(decode(o.type#, 2, 1, NULL)) tables, sum(decode(o.type#, 3, 1, NULL))clusters, sum(decode(o.type#, 4, 1, NULL)) views, sum(decode(o.type#, 5, 1,NULL)) synonyms, sum(decode(o.type#, 6, 1, NULL)) sequences,sum(decode(o.type#, 1, NULL, 2, NULL, 3, NULL, 4, NULL, 5, NULL, 6, NULL, 1))others from sys.obj$ o, sys.user$ u where o.type# >= 1 and u.user# =o.owner# and u.name <> 'PUBLIC' group by u.name order bysys.link$ union select 'CONSTRAINT' , count(*) from sys.con$23。有关connection的相关信息1）查看有哪些用户连接select s.osuser os_user_name, decode(sign(48 - command), 1, to_char(command),'Action Code #' || to_char(command) ) action, p.program oracle_process,status session_status, s.terminal terminal, s.program program,s.username user_name, s.fixed_table_sequence activity_meter, '' query,0 memory, 0 max_memory, 0 cpu_usage, s.sid, s.serial# serial_numfrom v$session s, v$process p where s.paddr=p.addr and s.type = 'USER'order by s.username, s.osuser2）根据v.sid查看对应连接的资源占用等情况select n.name,v.value,n.class,n.statistic#from v$statname n,v$sesstat vwhere v.sid = 71 andv.statistic# = n.statistic#order by n.class, n.statistic#3）根据sid查看对应连接正在运行的sqlselect /* PUSH_SUBQ */command_type,sql_text,sharable_mem,persistent_mem,runtime_mem,sorts,version_count,loaded_versions,open_versions,users_opening,executions,users_executing,loads,first_load_time,invalidations,parse_calls,disk_reads,buffer_gets,rows_processed,sysdate start_time,sysdate finish_time,'>' || address sql_address,'N' statusfrom v$sqlareawhere address = (select sql_address from v$session where sid = 71)24．查询表空间使用情况select a.tablespace_name "表空间名称",100-round((nvl(b.bytes_free,0)/a.bytes_alloc)*100,2) "占用率(%)",round(a.bytes_alloc/1024/1024,2) "容量(M)",round(nvl(b.bytes_free,0)/1024/1024,2) "空闲(M)",round((a.bytes_alloc-nvl(b.bytes_free,0))/1024/1024,2) "使用(M)",Largest "最大扩展段(M)",to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') "采样时间"from (select f.tablespace_name,sum(f.bytes) bytes_alloc,sum(decode(f.autoextensible,'YES',f.maxbytes,'NO',f.bytes)) maxbytesfrom dba_data_files fgroup by tablespace_name) a,(select f.tablespace_name,sum(f.bytes) bytes_freefrom dba_free_space fgroup by tablespace_name) b,(select round(max(ff.length)*16/1024,2) Largest,ts.name tablespace_namefrom sys.fet$ ff, sys.file$ tf,sys.ts$ tswhere ts.ts#=ff.ts# and ff.file#=tf.relfile# and ts.ts#=tf.ts#group by ts.name, tf.blocks) cwhere a.tablespace_name = b.tablespace_name and a.tablespace_name = c.tablespace_name25. 查询表空间的碎片程度select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_namehaving count(tablespace_name)>10;alter tablespace name coalesce;alter table name deallocate unused;create or replace view ts_blocks_v asselect tablespace_name,block_id,bytes,blocks,'free space' segment_name from dba_free_spaceunion allselect 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_spacegroup by tablespace_name;26.查看有哪些实例在运行：select * from v$active_instances;12:15 PM | Add a comment | Permalink | Blog it | OracleORACLE性能调优原则数据库的硬件配置：CPU、内存、网络条件1.         CPU：在任何机器中CPU的数据处理能力往往是衡量计算机性能的一个标志，并且ORACLE是一个提供并行能力的数据库系统，在CPU方面的要求就更高了，如果运行队列数目超过了CPU处理的数目，性能就会下降，我们要解决的问题就是要适当增加CPU的数量了，当然我们还可以将需要许多资源的进程KILL掉；2.         内存：衡量机器性能的另外一个指标就是内存的多少了，在ORACLE中内存和我们在建数据库中的交换区进行数据的交换，读数据时，磁盘I/O必须等待物