Oracle 系统调优

一：前言

一：调整初始化参数

1： Oracle 初始化参数分类

2：主要系统调优参数介绍

二：系统全局区 sga 优化

1：调整内存分配

2：调整日志缓冲区

1：查询当前oracle 实例的日志缓冲区的大小

  1
  2 SYS@orcl> select distinct lebsz as log_cache_size  from x$kccle;
  3
  4 LOG_CACHE_SIZE
  5 --------------
  6            512
  7              0
  8
  9 SYS@orcl>

3：调整共享池

  1
  2 SYS@orcl> select sum(pins) as sum_pins/*请求存取数*/,sum(reloads) as sum_reloads /*不命中数*/ from v$librarycache;
  3
  4   SUM_PINS SUM_RELOADS
  5 ---------- -----------
  6   11151706       52931
  7
  8 SYS@orcl>

  1 SYS@orcl> select sum(gets) as sum_pins /*请求存取数*/,sum(getmisses) as sum_reloads/*不命中数*/ from v$rowcache;
  2
  3   SUM_PINS SUM_RELOADS
  4 ---------- -----------
  5   14853534      220272
  6
  7 SYS@orcl>
  8 

  1 SYS@orcl> select sum(value)||'字节' as value_byte /*当前分配给所有会话的内存数*/  from v$sesstat a ,v$statname b where name='session uga memory' and a.statistic#=b.statistic#;
  2 VALUE_BYTE
  3 --------------------------------------------
  4 8376368字节
  5
  6 SYS@orcl>

  1 SYS@orcl> select sum(value)||'字节' as value_type /*曾经分配给所有会话的最大内存数*/ from v$sesstat a,v$statname b where name='session uga memory max' and a.statistic#=b.statistic#;
  2
  3 VALUE_TYPE
  4 --------------------------------------------
  5 25527396字节
  6
  7 SYS@orcl>

4：调整数据库缓冲区

示例：查询一段时间内 v$sysstat表中的统计信息

  1 SYS@orcl> select name ,value from v$sysstat where name in ('db block gets','consistent gets','physical reads');
  2
  3 NAME                                                                  VALUE
  4 ---------------------------------------------------------------- ----------
  5 db block gets                                                          2445
  6 consistent gets                                                      145199
  7 physical reads                                                         8414
  8
  9 SYS@orcl>

5：SGA调优建议

三：排序区优化

  1 SYS@orcl> show parameter sort_area_size;
  2
  3 NAME                                 TYPE        VALUE
  4 ------------------------------------ ----------- ------------------------------
  5 sort_area_size                       integer     65536
  6
  7 SYS@orcl> show parameter sort_area_
  8
  9 NAME                                 TYPE        VALUE
 10 ------------------------------------ ----------- ------------------------------
 11 sort_area_retained_size              integer     0
 12 sort_area_size                       integer     65536
 13 SYS@orcl>

1：排序区与其他内存区的关系

  1
  2 SYS@orcl> show parameter large_pool_size;
  3
  4 NAME                                 TYPE        VALUE
  5 ------------------------------------ ----------- ------------------------------
  6 large_pool_size                      big integer 0
  7 SYS@orcl> alter system set large_pool_size=32M;
  8
  9 System altered.
 10
 11 SYS@orcl> show parameter large_pool_size ;
 12
 13 NAME                                 TYPE        VALUE
 14 ------------------------------------ ----------- ------------------------------
 15 large_pool_size                      big integer 32M
 16 SYS@orcl>

2：排序活动

3：专用模式下排序区的调整

1：sort_area_size

2：sort_area_retained_size

示例：查看所有服务器进程使用的内存的总量

  1 SYS@orcl> show parameter pga_aggregate_target;
  2
  3 NAME                                 TYPE        VALUE
  4 ------------------------------------ ----------- ------------------------------
  5 pga_aggregate_target                 big integer 0
  6 SYS@orcl>

示例：查看 PGA使用的管理方式

  1 SYS@orcl> show parameter workarea_size_policy;
  2
  3 NAME                                 TYPE        VALUE
  4 ------------------------------------ ----------- ------------------------------
  5 workarea_size_policy                 string      AUTO
  6 SYS@orcl>

示例：查看会话信息及堆栈空间的大小

  1 SYS@orcl> show parameter sort_area_size;
  2
  3 NAME                                 TYPE        VALUE
  4 ------------------------------------ ----------- ------------------------------
  5 sort_area_size                       integer     65536
  6 SYS@orcl>

4：共享模式下排序区的调整

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