这里从DBImpl::MaybeScheduleFlushOrCompaction开始讲起。DBImpl::MaybeScheduleFlushOrCompaction可能会scheduleDBImpl::BGWorkFlush和DBImpl::BGWorkCompaction。这里主要看Flush。Compaction部分见：{%post_linkStorage/'RocksDB代码分析——Compaction流程'%}DBImpl::BGWo