log file sync 求解惑

311ybb

在Troubleshooting: "log file sync" Waits [ID 1376916.1]这篇文档里介绍减缓logfile sync等待事件的方法
Check to see if redo logs are large enough
A 'log file sync' operation is performed every time the redo logs switch to the next log to ensure that everything is written before the next log is started. Standard recommendations are that a log switch should occur at most once every 15 to 20 minutes. If switches occur more frequently than this, then more 'log file sync' operations will occur meaning more waiting for individual sessions.

红色字体部分爱怎么理解，logfile sync和log file  switch的关系？

card_2005

log file  switch会触发logfile sync等待事件，在下一个redo使用前确保log buffer的信息都写入到磁盘