?????κ????鶼????????????????????????????????ORACLE??????????????????????·??棺
??????????????????CPU???????????????
????1.CPU?????κλ?????CPU????????????????????????????????????????????ORACLE????????????????????????????CPU????????????????????ж????????????CPU????????????????????????????????????????????CPU????????????????????????????????????KILL???
????2.??棺?????????????????????????????????????ORACLE???????????????????е?????????????????????????????????I/O??????????I/O?????????????ORACLE?????????????????????????????????棬????I/O?????????????ORACLE??????????????????????????????????
????3.??????????NET*SQL?????????????????????????????SQL????????????????????10M????????100????????NET*SQL?з?????????????н?????????????????????豸????????????????????????????κ??????в???????3???????????????λ?????
????OS??????????
????OS????????ü??????DBA?????????????????Щ????????????
???????SQL????
???????????????????????????????????????????￡?????????????ó????SQL??????
????1.????????????裨Full"Table Scan?????????赼?′?????I/O
????2.???????ú???ú?????????????????н??????????????????????????????????????????????4?????????ORACLE??????????????????????OLTP????????5??????????????????????????sql?У?Oracle???????ó???5?????????????????GROUP BY??ORDER BY???ORACLE????????????????????ORACLE??INIT.ORA?о?????sort_area_size?????С?????????????????????????????????ORACLE????????н??????????????????????????????????????????????free buffer waits?????????????????????????????????????????????????????:
????1)??select??update??delete????е?????????й???????????20%?????.?????????????????????????????20%?????????????????????????????????.
????2??????????????????????????????????????????????????????.?????????????????????????????????????.?????????????????????????????????????????????????????????????????????????.???????????￡???????????truncate???truncate??????????????м???????????????.
????3?????????????????????????????ε??????????á?
????4???????+??????NOT IN????Ч???
????????ORACLE???????
???????????ORACLE????????????????????????ORACLE???????
????1????freelists??freelist?飺???????ORACLE???????????????????
????2????pctfree??pctused???ò?????????freelists??freelist????????pctfree??pctused???????????????????????freelists?н???
???????ú?pctfree??pctused?????freelists????????????????
??????????????????
????1????????SGA????????????????????????SGA????????????Oracle????????Oracle????????????????????Ρ?
??????????????????????(the database buffer cache)??
??????????????棨the redo log buffer????
??????????the shared pool????
??????????仺?棨the data dictionary cache???????????????????
????2????db_block_buffers????????????????????????????????????????????ò??????Oracle????????????????????????????????????????
????3????share_pool_size??SQL????????????ò??????????????????????????檔
????4????Log_buffer?????????????????
????5????sort_area_size??????????
????6????processes????????????????
????7????db_block_size?????????С????Oracle?????2KB???С??????????????????8KB?????????2KB???????????4??????????????8KB??????????1?ζ??????????????I/O????????????????????????db_block_size????????????????????????????????????????????
????8????open_links????????????????
????9????dml_locks
????10????open_cursors???????????
????11????dbwr_io_slaves?????д????????