ORACLE:

REDO LOG

系统警告说REDOLOGWriter经常时间长经常200多ms
怎么调整？

SPOT LIGTH 给出警告。

Severity:High

Reason:Average redo log write time is 118 ms (averaged over 30 seconds)

RedoLogwriter(LGWR)
TheRedologwriterwritestheredobufferblocksfromSGAtoredologfilesontheharddisk.
Analarmcanbecomecurrentonthisprocessiflogswitchwaitsoccur(LogSwitchTimealarm),oriftheaverageredoI/Otimeexceedsathreshold(AverageTimetoSyncaRedoLogEntryalarm).

调整：

1、调整redo log buffer大小：512K *cpu个数或218* cpu个数（cpu_COUNT）
2、调优redo_log_buffer

查看版本：

select * from v$version where rownum<2;

select * from v$sgainfo where name in ('Fixed SGA Size','Redo Buffers','Granule Size');