11g~安裝後的調整

1.  11g預設audit_trail會開啟，若確認未使用，建議將此參數關閉(須重啟DB生效)，目前該DB已有將audit相關table 與index 存放到non system or sysaux tablespace，若確認須使用建議要有定其排程刪除其audit資料。

alter system set audit_trail=NONE scope=spfile;

SQL> show parameter audit

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
audit_file_dest                      string      /opt/oracle/admin/topprod/adump
audit_sys_operations                 boolean     FALSE
audit_syslog_level                   string
audit_trail                          string      DB

TABLE_NAME                     TABLESPACE_NAME
------------------------------ ------------------------------
AUD$                           AUDTBS

 

SQL> select index_name,tablespace_name from dba_indexes where table_name='AUD$';

INDEX_NAME                     TABLESPACE_NAME
------------------------------ ------------------------------
SYS_IL0000000407C00040$$       AUDTBS
SYS_IL0000000407C00041$$       AUDTBS

2. UNDO TABELSPACE datafile SIZE建議調整，目前undo tablespace 之datafile 為1g maxsize 無限制，此設定會造成oracle自行再調整undo_retention時會有錯亂的問題(10g 11g皆如此)，建議調整datafile current size與autoextend max szie相當，以避免造成oracle自行tune undo retention時因錯亂而造成expired的空間不被重複使用。(此可online調整)

SQL> select tablespace_name,bytes/1024/1024 "MB" ,maxbytes/1024/1024 "MAX"
  2  from dba_data_files
  3  where tablespace_name='UNDOTBS1';


TABLESPACE_NAME                        MB        MAX
------------------------------ ---------- ----------
UNDOTBS1                             1060 32767.9844

* 建議用固定大小(create-crrent size/max size)10G/10GB or 5G/10G,之後要監控實際用量後再調整!

* 建議至少用兩個 datafile。

Callstack:
    at User:Alang/IT_專案工作/Oracle_DBA_筆記/Oracle_Installation/Oracle_11g_Tips/11g~安裝後的調整

MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException: reference to undefined name 'syntax' Exception of type 'MindTouch.Deki.Script.Runtime.DekiScriptUndefinedNameException' was thrown.
  at MindTouch.Deki.Script.Compiler.DekiScriptExpressionEvaluation.Visit (MindTouch.Deki.Script.Expr.DekiScriptVar expr, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Expr.DekiScriptVar.VisitWith[DekiScriptExpressionEvaluationState,Range] (IDekiScriptExpressionVisitor`2 visitor, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Compiler.DekiScriptExpressionEvaluation.Evaluate (MindTouch.Deki.Script.Expr.DekiScriptAccess expr, DekiScriptExpressionEvaluationState state, Boolean evaluateProperties) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Compiler.DekiScriptExpressionEvaluation.Visit (MindTouch.Deki.Script.Expr.DekiScriptAccess expr, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Expr.DekiScriptAccess.VisitWith[DekiScriptExpressionEvaluationState,Range] (IDekiScriptExpressionVisitor`2 visitor, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Compiler.DekiScriptExpressionEvaluation.Visit (MindTouch.Deki.Script.Expr.DekiScriptCall expr, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Expr.DekiScriptCall.VisitWith[DekiScriptExpressionEvaluationState,Range] (IDekiScriptExpressionVisitor`2 visitor, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Compiler.DekiScriptExpressionEvaluation.Visit (MindTouch.Deki.Script.Expr.DekiScriptSequence expr, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Expr.DekiScriptSequence.VisitWith[DekiScriptExpressionEvaluationState,Range] (IDekiScriptExpressionVisitor`2 visitor, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 
  at MindTouch.Deki.Script.Compiler.DekiScriptExpressionEvaluation.Visit (MindTouch.Deki.Script.Expr.DekiScriptReturnScope expr, DekiScriptExpressionEvaluationState state) [0x00000] in <filename unknown>:0 

3. invisible parameter modify (restart instance) 此為11.2.0.2之後被引進的新的特性，建議關閉此新特性，此新特性會造成log_file_sync的mode一直切換而造成lgwr在將log_buffer寫到redo log file的速度異常的慢，若嚴重時可能造成所有session hang住(修改須重啟instance生效)

alter system set "_use_adaptive_log_file_sync"=false scope=spfile; (修改須重啟instance)

(/opt/oracle/diag/rdbms/topprod/topprod/trace/topprod_lgwr_19156.trc) 可以觀察到

4. (online可修改生效) 關閉11g 新功能 _OPTIMIZER_USE_FEEDBACK，此為11g optimizer新特性，容易造成已固定execution plan又變化而造成效能問題，建議關閉。

alter system set "_OPTIMIZER_USE_FEEDBACK"=FALSE scope=both;

5. (online可修改生效) for Big size (DB) 大型資料庫 尤其有一個table 好幾十G的，建議將此參數關閉，當此參數開啟時預設為2，可能為因table size較大而oracle會自行決定所有程式在執行時不再參考該table統計職而啟用

alter system set optimizer_dynamic_sampling=0 scope=both;

---此為可立即修改
SQL> select ISSYS_MODIFIABLE from v$parameter where name='optimizer_dynamic_sampling';
ISSYS_MOD

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IMMEDIATE