mongodb geoNear vs附近 [英] mongodb geoNear vs near
问题描述
似乎mongodb为地理空间查询提供了两个类似的功能-$near
和$geoNear
.根据mongo文档
It looks like mongodb offers two similar functions for geospatial queries - $near
and $geoNear
. According to the mongo docs
geoNear命令提供了$ near运算符的替代方法.在 除了$ near的功能外,geoNear还返回其他 诊断信息.
The geoNear command provides an alternative to the $near operator. In addition to the functionality of $near, geoNear returns additional diagnostic information.
看起来geoNear
提供了near
功能的超集.例如,near
似乎仅返回最接近的100个文档,而geoNear
允许您指定最大值.是否有理由使用near
而不是geoNear
?一个比另一个更有效吗?
It looks like geoNear
provides a superset of the near
functionality. For example, near
seems to only return the closest 100 documents, whereas geoNear
lets you specify a maximum. Is there a reason to use near
instead of geoNear
? Is one more efficient than the other?
推荐答案
两者的效率均应相同.
Efficiency should be identical for either.
geoNear
的主要限制是,作为命令,它可以返回最大文档大小的结果集,因为所有匹配的文档都在单个结果文档中返回.它还要求在每个结果文档中添加一个距离字段,根据您的使用情况,该字段可能会或可能不会成为问题.
geoNear
's major limitation is that as a command it can return a result set up to the maximum document size as all of the matched documents are returned in a single result document. It also requires that a distance field be added to each result document which may or may not be an issue depending on your usage.
$near
是查询运算符,因此结果可以大于单个文档(它们仍在单个响应中返回,但不是单个文档).您还可以通过查询的limit()设置最大文档数.
$near
is a query operator so the results can be larger than a single document (they are still returned in a single response but not a single document). You can also set the maximum number of documents via the query's limit().
我倾向于建议用户坚持使用$near
,除非他们需要geonear
命令中的diagnostics
(例如,距离或位置匹配).
I tend to recommend that users stick with the $near
unless they need the diagnostics
(e.g., distance, or location matched) from the geonear
command.
这篇关于mongodb geoNear vs附近的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!