151. 如何監控 SGA 中字典緩衝區的命中率？

select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100

"miss ratio",

(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"

from v$rowcache

where gets+getmisses <>0

group by parameter, gets, getmisses;

152. 如何監控 SGA 中共用緩存區的命中率，應該小於1% ？

select sum(pins) "Total Pins", sum(reloads) "Total Reloads",

sum(reloads)/sum(pins) *100 libcache

from v$librarycache;

select sum(pinhits-reloads)/sum(pins) "hit

radio",sum(reloads)/sum(pins) "reload percent"

from v$librarycache;

153. 如何顯示所有資料庫物件的類別和大小？

select count(name) num_instances ,type ,sum(source_size)

source_size ,

sum(parsed_size) parsed_size ,sum(code_size) code_size

,sum(error_size) error_size,

sum(source_size) +sum(parsed_size) +sum(code_size)

+sum(error_size) size_required

from dba_object_size

group by type order by 2;

154. 監控 SGA 中重做日誌緩存區的命中率，應該小於1%

SELECT name, gets, misses, immediate_gets, immediate_misses,

Decode(gets,0,0,misses/gets*100) ratio1,

Decode(immediate_gets+immediate_misses,0,0,

immediate_misses/(immediate_gets+immediate_misses)*100) ratio2

FROM v$latch WHERE name IN (''''redo allocation'''', ''''redo copy'''');

155. 監控記憶體和硬碟的排序比率，最好使它小於 .10，增加 sort_area_size

SELECT name, value FROM v$sysstat WHERE name IN (''''sorts (memory)'''',

''''sorts (disk)'''');

156. 如何監控當前資料庫誰在運行什麽SQL語句？

SELECT osuser, username, sql_text from v$session a, v$sqltext b

where a.sql_address =b.address order by address, piece;

157. 如何監控字典緩衝區？

SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM

V$LIBRARYCACHE;

SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW

CACHE" FROM V$ROWCACHE;

SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE

EXECUTING" FROM V$LIBRARYCACHE;

後者除以前者,此比率小於1%,接近0%爲好。

SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY

CACHE GET MISSES"

FROM V$ROWCACHE

158. 監控 MTS

select busy/(busy+idle) "shared servers busy" from v$dispatcher;

此值大於0.5時，參數需加大

select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where

type=''''dispatcher'''';

select count(*) from v$dispatcher;

select servers_highwater from v$mts;

servers_highwater接近mts_max_servers時，參數需加大

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