DBWn写规则 作为oracle数据文件写入进程,DBWn写规则在百度上有多种版本,其实翻看oracle官方文档。只有2种情况DBWn进程才会写:database buffer cache空间不足和instance 恢复。 The DBWn process writes dirty buffers to diskunder the following conditions: · When aserver process cannot find a clean reusable buffer after scanning a thresholdnumber of buffers, it signals DBWn to write. DBWn writes dirty buffers to diskasynchronously if possible while performing other processing. · DBWn periodicallywrites buffers to advance the [url=]checkpoint[/url],which is the position in the [url=]redo thread[/url] from which instance recovery begins (see [url=]"Overview of Checkpoints"[/url]). The log position of the checkpoint is determined by theoldest dirty buffer in the buffercache.
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