The "what-if analysis" USES a virtual index under the covers to assess the effective of the indexes.

“如果这样会怎样的分析”使用了虚拟索引来评估索引的效果。

youdao

The tool cannot only be used to get Suggestions for the various grid sizes but also to collect statistics of an existing or planned (virtual) index.

该工具不仅可用于获得关于各种不同网格大小的建议，还可以用于收集一个已有的或计划中的(虚)索引的统计信息。

youdao

Also keep in mind that on AIX, there is approximately a Max of 250mb of private virtual memory for index key sorting in LOAD (this is a memory bottleneck).

还请记住，AIX上大约有最大为250 MB的私有虚拟内存用于LOAD中的索引键排序(这是内存瓶颈)。

youdao

With a virtual 6 x 9 inch color VGA display, a small joy stick and mouse buttons operable by the index finger when using the phone during a conversation the StarTac phone provided the ability to viewed shared subject matter, photos or documents while talking, 15 years ago.

FORBES: The Cyber Display Telephone