高水位线是段中已用和未用空间的边界。

The high water mark is the boundary between used and unused space in a segment.

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确保数据库可以打开的数据库探测器(该探测器也可以检查数据库的未用空间和不活动的用户)。

A database probe that ensures a database can be opened (Optionally, the probe can check the database for unused space and user inactivity.)

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但是大量未用的接轨舱门显示出潜在的扩充空间。

However the large number of unused docking ports indicated substantial room for expansion.

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