它由相互对应的索引标志和制成隐形标志的识别标志构成。

It is composed of mutual corresponding index marks and distinguishing mark having been made into concealed one.

youdao

更好的控制手工索引和索引编写（RAM使用、非混合的文件格式标志等等）。

Better control over manual indexing and index writing (RAM consumption, non-compound file format flag etc).

youdao

重新生成索引的速度更快(让未改变的部分保持打开)并且读取索引时的并发性更好(使用了只读标志)。

Faster index reopening (keeps unchanged segments opened) and better index reader concurrency (use of the read only flag).

youdao