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标题:
Oracle 19c RAC 为了避免一些不必要的bug设定参数
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作者:
mahan
时间:
2024-9-8 17:19
标题:
Oracle 19c RAC 为了避免一些不必要的bug设定参数
1.关闭自适应游标共享参数
为了避免oracle 19c 遇到自适应游标共享(隐藏参数)会带来过多子游标和ORA-04031问题。将其先关闭。
[grid@node1 ~]$
[grid@node1 ~]$ sqlplus / as sysasm
SQL*Plus: Release 19.0.0.0.0 - Production on Thu Nov 10 17:22:43 2022
Version 19.3.0.0.0
Copyright (c) 1982, 2019, Oracle. All rights reserved.
Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0
SQL> alter system set "_optimizer_adaptive_cursor_sharing"=false sid='*' scope=spfile;
System altered.
SQL> alter system set "_optimizer_extended_cursor_sharing"=none sid='*' scope=spfile;
System altered.
SQL> alter system set "_optimizer_extended_cursor_sharing_rel"=none sid='*' scope=spfile;
System altered.
SQL>
2.关闭RAC隐藏参数"_gc_bypass_reader"和 "_gc_read_mostly_lock"
为了避免RAC的用户进程卡死在内部等待 "gc current request"这个数据库内部等待,大多与隐藏参数"_gc_bypass_reader"和 "_gc_read_mostly_lock"有关系,关闭参数可以减少bug并且不会影响性能,因此建议关闭。
alter system set "_gc_bypass_readers"=false;
alter system set "_gc_read_mostly_locking"=false;
3.关闭RAC全局事务支持隐藏参数
alter system set "_clusterwide_global_transactions"=false sid='*' scope=spfile;
4.关闭跨实例并行参数
alter system set parallel_force_local=true scope=spfile sid='*';
5.关闭Cardinality feedback
12c版本的Cardinality feedback可能会导致执行计划的不稳定,为了避免19c发生,建议关闭:
alter system set "_optimizer_use_feedback"=false sid ='*' scope=spfile;
6.关闭UNDO_RETENTION的自动调整
避免undo自动调整发生的一系列bug:
alter system set "_undo_autotune"=false scope=spfile sid='*';
alter system set undo_retention=10800 scope=spfile sid='*';
7.关闭DRM的相关隐藏参数
alter system set "_gc_policy_time"=0 scope=spfile sid='*';
alter system set "_gc_undo_affinity"=false sid='*';
8.关闭result_cache
alter system set result_cache_max_size=0 scope=spfile sid='*';
9.关闭初始化extent的延迟创建功能
alter system set deferred_segment_creation=false scope=spfile sid='*';
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