???????????????
?????????????????????ORACLE???????????????SGA?????????SGA???????????????????????????????????????????
????1??   ?????????????????????SQL??????????仺??????????SQL?????????SQL???????????????仺???????????????е??????????????????????????????
????select (sum(pins -reloads)) / sum(pins) "Lib Cache" from v$librarycache;
????????????SQL?????????????????????90????????????????????????С???????????????????????????
????select (sum(gets - getmisses - usage - fixed))/ sum(gets) "Row Cache" from v$rowcache;
????????????仺??????????????????????????90????????????????????????С??
????2??   ?????????.???????????????????????
????SELECT name?? value  FROM v$sysstat  WHERE name IN ('db block gets'?? 'consistentgets'??'physical reads');
??????????????????????????????????????????????????????????????????????????1 - ( physical reads / (db block gets + consistent gets))??
??????????????????90??????????????????????????????С??
????3??   ?????????.??????????????????????????
????select name??value from v$sysstat where name in('redo entries'??'redo log space requests');???????????????????????????????????????????????????????????
??????????????requests/entries?????????????y????0???????????????????????С?????????ORACLE?????????????????