java - 复合索引是否支持索引字段前缀的匹配？

Question

考虑我有以下集合结构

"mycoll":{
    "a":"",
    "b":"",
    "c":"",
    "d":"",
    "e":""
}

我有类似的索引

{
    "a":1,
    "b":1,
    "c":1,
    "e":1
}

我的查询就像(查询中的字段“d”不在索引中)

db.mycoll.find({"a":"?","b":"?","c":"?","d":"?"});

请告诉我我的索引是否支持上述查询？

Answer 1

是的，复合索引支持与前缀匹配的查询索引字段。

In addition to supporting queries that match on all the index fields, compound indexes can support queries that match on the prefix of the index fields.

Compound Index

我已经用explain()检查了您的查询，获胜计划确实使用了索引扫描。

db.mycoll.find({"a":"?","b":"?","c":"?","d":"?"});

"stage" : "IXSCAN"