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$mts;
servers_highwater接近mts_max_servers時，參數需加大
159. 如何知道當前用戶的ID號
SQL>SHOW USER;
OR
SQL>select user from dual;
160. 如何查看碎片程度高的表
SELECT segment_name table_name , COUNT(*) extents
FROM dba_segments WHERE owner NOT IN ('SYS', 'SYSTEM') GROUP BY
segment_name
HAVING COUNT(*) = (SELECT MAX( COUNT(*) ) FROM dba_segments GROUP
BY segment_name);
162. 如何知道表在表空間中的存儲情況
select segment_name,sum(bytes),count(*) ext_quan from dba_extents
where
tablespace_name='&tablespace_name' and segment_type='TABLE' group
by tablespace_name,segment_name;
163. 如何知道索引在表空間中的存儲情況
select segment_name,count(*) from dba_extents where
segment_type='INDEX' and owner='&owner'
group by segment_name;
164、如何知道使用CPU多的用戶session
11是cpu used by this session
select a.sid,spid,status,substr(a.program,1,40)
prog,a.terminal,osuser,value/60/100 value
from v$session a,v$process b,v$sesstat c
where c.statistic#=11 and c.sid=a.sid and a.paddr=b.addr order by
value desc;
165. 如何知道監聽器日誌文件
以8I爲例
$ORACLE_HOME/NETWORK/LOG/LISTENER.LOG
166. 如何知道監聽器參數文件
以8I爲例
$ORACLE_HOME/NETWORK/ADMIN/LISTENER.ORA
167. 如何知道TNS 連接文件
以8I爲例
$ORACLE_HOME/NETWORK/ADMIN/TNSNAMES.ORA
168. 如何知道Sql*Net 環境文件
以8I爲例
$ORACLE_HOME/NETWORK/ADMIN/SQLNET.ORA
169. 如何知道警告日誌文件
以8I爲例
$ORACLE_HOME/ADMIN/SID/BDUMP/SIDALRT.LOG
170. 如何知道基本結構
以8I爲例
$ORACLE_HOME/RDBMS/ADMIN/STANDARD.SQL
171. 如何知道建立資料字典視圖
以8I爲例
$ORACLE_HOME/RDBMS/ADMIN/CATALOG.SQL
172. 如何知道建立審計用資料字典視圖
以8I爲例
$ORACLE_HOME/RDBMS/ADMIN/CATAUDIT.SQL
173. 如何知道建立快照用資料字典視圖
以8I爲例
$ORACLE_HOME/RDBMS/ADMIN/CATSNAP.SQL
本講主要講的是SQL語句的優化方法! 主要基於ORACLE9I的.
174. /*+ALL_ROWS*/
表明對語句塊選擇基於開銷的優化方法,並獲得最佳吞吐量,使資源消耗最小化.
例如:
SELECT /*+ALL+_ROWS*/ EMP_NO,EMP_NAM,DAT_IN FROM BSEMPMS WHERE