???? I/O ??

1 UNIX ??????? Windows ???????????????????????? Disk rate ????????ò?????????????? I/O ??????????????????????????

2 Windows ???????У???? Disk Time ?? Avg.Disk Queue Length ????????? Page Reads/sec ????????????????????????????????

I/O ?????????????????????? :

*?????????????? (high disk utilization)

*?????????????? (large disk queue length)

*??????? I/O ????????????????? (large percentage of time waiting for disk I/O)

*???????? I/O ???? :large physical I/O rate(not sufficient in itself)

*?????????????? (low buffer cache hit ratio(not sufficient in itself))

*????????н?????У??? CPU ????? (large run queue with idle CPU)

4 ??????????????

SQL Server ?????

1 SQLServer ?????????????????? Cache Hit Ratio ????????????á???????????? 80% ?????????????檔

2 ??? Full Scans/sec ???????? / ???????????????? 1 ?? 2 ?????????????????????????????????裬??? SQL ???????????????

3 Number of Deadlocks/sec( ?????????? / ?? ) ??????????ó??????????????к????????????????????顣?ü????????????? 0 ??

4 Lock Requests/sec( ?????? / ?? ) ????????????????????????????????ü??????????

Oracle ?????

1 ?????????????? 0 ????????????????????????С?? 0.90 ???????????? SHARED_POOL_SIZE ???С??

??棨???? SQL ???????????????????????

select(sum(pins-reloads))/sum(pins) from v$librarycache;

select(sum(gets-getmisses))/sum(gets) from v$rowcache;

??????棺 select * from v$sgastat where name= ’ free memory ’ ;

2 ?????????????????С?? 0.90 ??????????? DB_BLOCK_BUFFERS ???????????λ???飩??

????????????????????

select name??value from v$sysstat where name in (’db block gets’??

‘ consistent gets’??'physical reads’) ;

Hit Ratio = 1-(physical reads / ( db block gets + consistent gets))

3 ??????????????????????????? LOG_BUFFER ?????????

?????????????????? ??

select name??value from v$sysstat where name = ‘redo log space requests’ ;

4 ????????????????С?? 0.95 ???????? SORT_AREA_SIZE ???????????? ??

????????????? ??

select round((100*b.value)/decode((a.value+b.value)?? 0?? 1?? (a.value+b.value))?? 2)from v$sysstat a?? v$sysstat b where a.name=’sorts (disk)’ and b.name=’sorts (memory)’

??????? SQL Server ?? Oracle ??????????????Щ???????????????????? Oracle ???????????????????????????????????????????????????
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