1z0-024考点总结

2. Tuning overview 1

(1) 调整的先后次序

1. Tune the design. -- Application designers

2. Tune the application. -- Application developers

3. Tune memory. --|

4. Tune I/O. |-- DBA

5. Tune contention. |

6. Tune the operating system. --|

(2) 调整的基点和主要的可测量的目标

Database hit percentages 命中率是base line

SQL statements access the smallest possible number of Oracle blocks 访问尽可能少的数据块

response time, database xdyailability, memory utilization(页面交换)等

3. Oracle Alert and Trace Files 2

(1) USER_DUMP_DEST和BACKGROUD_DUMP_DEST

USER_DUMP_DEST: SQL_TRACE, DEAD LOCK, 用户session中sql语句的执行情况

BACKGROUD_DUMP_DEST: Alert.log, 系统后台进程的错误信息

(2) Alert.log文件的特性和内容

-- 启动时不存在则自动创建,存在BACKGROUD_DUMP_DEST路径下

-- 文件尺寸一直增长,需要人工清除

-- 包含内容有:

Internal errors (ORA-600), and block corruption errors (ORA-1578)

影响数据库结构,参数的操作,以及命令:CREATE DATABASE, STARTUP, SHUTDOWN, ARCHIVE LOG,RECOVER

实例启动时的非缺省参数 -- 启动时写入 控制文件和在线表空间备份

未完成的检查点

(3) SQL_TRACE设置的两个级别

Instance 参数中设定

Session ALTER SESSION SET SQL_TRACE=TRUE / DBMS_SYSTEM.SET_SQL_TRACE_IN_SESSION(sid,serial#,TRUE/FALSE)

(4) 参数MAX_DUMP_FILE_SIZE限制User Trace文件的O/S Blocks

4. Utilities and Dynamic Performance Views 3

(1) Anylyze执行之后查询信息的字典:

DBA_TABLES and DBA_TAB_COLUMNS table storage within extents and blocks

DBA_HISTOGRAMS and INDEX_HISTOGRAM data about nonindexed and indexed column data distribution.

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