elasticsearch - 索引别名在Elasticsearch中如何工作？

Question

我想知道索引别名在Elasticsearch的幕后究竟如何工作？

对于别名所链接的每个索引，别名是否具有单独的数据副本？还是只知道索引名称，而不知道每个索引中的数据？

如果是这种情况，对具有许多链接索引的别名执行聚合时，聚合速度会慢很多吗？

Answer 1

从Index Aliases Elasticsearch引用中:

APIs in elasticsearch accept an index name when working against a specific index, and several indices when applicable. The index aliases API allow to alias an index with a name, with all APIs automatically converting the alias name to the actual index name. An alias can also be mapped to more than one index, and when specifying it, the alias will automatically expand to the aliases indices. An alias can also be associated with a filter that will automatically be applied when searching, and routing values.

因此，基于此，它仅知道索引名称，而不知道每个索引中的数据。对跨越多个索引的别名执行聚合时，速度可能会变慢。据我所知，为了执行聚合操作，Elasticsearch必须收集数据集以执行聚合功能。