BUFFER HIT RATIO NOTES

2010.06.15 20:37

조인상 조회 수:14125

원문 : http://www.ischo.net -- 조인상 // 시스템 엔지니어

Writer : http://www.ischo.net -- ischo // System Engineer in Replubic Of Korea

+++++++++++++++++++++++++++++++++++++++++++++++++++++++

 

원문 : http://www.ischo.net -- 조인상 //시스템 엔지니어

+++++++++++++++++++++++++++++++++++++++++++++++++++++++

BUFFER HIT RATIO NOTES:
  • Consistent Gets - The number of accesses made to the block buffer to retrieve data in a consistent mode.
  • DB Blk Gets - The number of blocks accessed via single block gets (i.e. not through the consistent get mechanism).
  • Physical Reads - The cumulative number of blocks read from disk.

  • Logical reads are the sum of consistent gets and db block gets.
  • The db block gets statistic value is incremented when a block is read for update and when segment header blocks are accessed.
  • The buffer hit ratio (also known as read hit ratio) is one indicator that identifies whether to add more database block buffers. This buffer hit ratio identifies the difference between the number of reads from disk versus memory (found in the database block buffers).If your system is highly interactive, then a good rule of thumb is to ensure the buffer hit ratio is greater than 95 percent. If your system is highly batch reporting, then a good rule of thumb is to ensure the buffer hit ratio is greater than 85 percent. Keep in mind it is much faster to find data in memory than going to disk, therefore, if there is memory to increase the database block buffers without hurting system resources, then more memory should be added to this area to increase these percentages.
  • Hit Ratio should be > 85%, else increase DB_BLOCK_BUFFERS in init.ora
  • 번호 제목 글쓴이 날짜 조회 수
    75 Unix 에서 Raw Device 사용법 조인상 2010.05.12 17857
    74 imp 시의 속도향상을 위한 팁 조인상 2010.10.13 17721
    73 오라클 캐릭터셋 변경 조인상 2010.07.30 17181
    72 오라클 8.1.7 for windows [5] file 조인상 2010.07.01 16628
    71 아카이브 모드로 변환하기 조인상 2010.05.12 16425
    70 Master Note for Diagnosing ORA-4030 (Oracle Metalink) 조인상 2011.10.31 16386
    69 AIX 64bit - oracle 10.2.0.1 설치 file 조인상 2010.05.12 16201
    68 롤백세그먼트 부족에 대한 관리법 (ORA-01555) 조인상 2010.10.13 16182
    67 ORA-28002 : the password will expired within N days 조인상 2014.01.09 16131
    66 10G: ORA-6512 AT SYS.OLAPIHISTORYRETENTION [ID 266728.1] 조인상 2011.06.23 16013
    65 오라클 10g OCP 라이센스 업그레이드 정보 조인상 2010.05.12 15643
    64 Oracle 7.3.4 for Windows file 조인상 2011.08.31 15618
    63 오라클 홈디렉토리 변경 ( /oracle_backup => /oracle ) 조인상 2010.05.12 15556
    62 time-based recovery 조인상 2010.08.24 15376
    61 control file 재생성하기 조인상 2010.05.12 15349
    60 오라클 startup & shutdown 쉘 스크립트 짜는 법 조인상 2010.05.12 15213
    59 오라클 유저 생성 및 변경/삭제 조인상 2010.05.12 15018
    58 아카이브 로그 강제로 생성하는 명령어 조인상 2010.05.12 14729
    57 오라클 패치 후 export가 안된다! [1] 조인상 2010.05.12 14517
    56 10g ORA-32004 : obsolete and/or deprecated parameter(s) specified 조인상 2010.05.12 14218
    서버에 요청 중입니다. 잠시만 기다려 주십시오...