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;　

　　select　 name, waits, gets, waits/gets "Ratio"　　from　v$rollstat a, v$rollname b　　where　a.usn = b.usn;　

　　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;　

　　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#;　

　　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;　

　　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;