查询处于锁表中的表

SELECTl.session_idSID,l.locked_mode,l.oracle_username,l.os_user_name,s.machine,s.terminal,o.object_name,s.logon_time,s.serial#FROMv$locked_objectl,all_objectso,v$sessionsWHEREl.object_id=o.object_idANDl.session_id=s.SIDORDERBYSID,s.serial#;

删除掉系统锁定的此记录

ALTERSYSTEMKILLSESSION'SID,serial#';

查询最慢的sql

SELECT*FROM(SELECTparsing_user_id,executions,sortscommand_type,disk_reads,sql_textFROMv$sqlareaORDERBYdisk_readsDESC)WHEREROWNUM<10

消耗磁盘读取最多的sqltop5

SELECTdisk_reads,sql_textFROM(SELECTsql_text,disk_reads,DENSE_RANK()OVER(ORDERBYdisk_readsDESC)disk_reads_rankFROMv$sql)WHEREdisk_reads_rank<=5;

ORACLE分页查询

SELECT*FROM(SELECTROW_.*,ROWNUMROWNUM_FROM(SELECT*FROMTABLE_NAME)ROW_)WHEREROWNUM_>0ANDROWNUM_<=5

ORACLE查询一行数据

SELECT*FROM(SELECT*FROMTABLE_NAME)AWHEREROWNUM=1

查询IO大于10000的SQL

SELECTb.usernameusername,a.disk_readsREADS,a.executionsexec,a.disk_reads/decode(a.executions,0,1,a.executions)rds_exec_ratio,a.sql_textstatementFROMv$sqlareaa,dba_usersbWHEREa.parsing_user_id=b.user_idANDa.disk_reads>100000ORDERBYa.DISK_READSDESC;

解析时间大于执行时间

SELECTEXECUTIONS,DISK_READS,BUFFER_GETS,ROUND((BUFFER_GETS-DISK_READS)/BUFFER_GETS,2)Hit_radio,ROUND(DISK_READS/EXECUTIONS,2)Reads_per_run,SQL_TEXTFROMV$SQLAREAWHEREEXECUTIONS>0ANDBUFFER_GETS>0AND(BUFFER_GETS-DISK_READS)/BUFFER_GETS<0

性能最差SQL

SELECThash_value,executions,buffer_gets,disk_reads,parse_calls,sql_textFROMV$SQLAREAWHEREbuffer_gets>10000000ORdisk_reads>1000000ORDERBYbuffer_gets+100*disk_readsDESC;

查看表空间

SELECTUpper(F.TABLESPACE_NAME)"表空间名",D.TOT_GROOTTE_MB"表空间大小(M)",D.TOT_GROOTTE_MB-F.TOTAL_BYTES"已使用空间(M)",To_char(Round((D.TOT_GROOTTE_MB-F.TOTAL_BYTES)/D.TOT_GROOTTE_MB*100,2),'990.99')||'%'"使用比",F.TOTAL_BYTES"空闲空间(M)",F.MAX_BYTES"最大块(M)"FROM(SELECTTABLESPACE_NAME,Round(Sum(BYTES)/(1024*1024),2)TOTAL_BYTES,Round(Max(BYTES)/(1024*1024),2)MAX_BYTESFROMSYS.DBA_FREE_SPACEGROUPBYTABLESPACE_NAME)F,(SELECTDD.TABLESPACE_NAME,Round(Sum(DD.BYTES)/(1024*1024),2)TOT_GROOTTE_MBFROMSYS.DBA_DATA_FILESDDGROUPBYDD.TABLESPACE_NAME)DWHERED.TABLESPACE_NAME=F.TABLESPACE_NAMEORDERBY1;