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我有一个场景,其中“_id”字段包含嵌入式文档,并且在针对嵌入式文档中的字段使用时看到了比较运算符($ gte/$ lte)的奇怪行为。嵌入式文档上的MongoDB索引边界
例如考虑下面的收集有9个文档,每一个嵌入的文件为“_id”
db.DocumentWithCompoundKeyCollection.find()
{ "_id" : { "Part1" : 1, "Part2" : 1 }, "SomeValue" : BinData(3,"B8+yWvTV4kS/u3e6Cv8Kcw==") }
{ "_id" : { "Part1" : 1, "Part2" : 2 }, "SomeValue" : BinData(3,"eLS1ONAoGUawW+v+vQdFDQ==") }
{ "_id" : { "Part1" : 1, "Part2" : 3 }, "SomeValue" : BinData(3,"m7WsIyInIEmsgWUMcsJPAw==") }
{ "_id" : { "Part1" : 2, "Part2" : 4 }, "SomeValue" : BinData(3,"z7/2j0g4AUikqS5K1TzZig==") }
{ "_id" : { "Part1" : 2, "Part2" : 5 }, "SomeValue" : BinData(3,"WudfqGYE8U+YwWe3Q0qL1w==") }
{ "_id" : { "Part1" : 2, "Part2" : 6 }, "SomeValue" : BinData(3,"B60SpSmXdUGn6AJDu1JIzg==") }
{ "_id" : { "Part1" : 3, "Part2" : 7 }, "SomeValue" : BinData(3,"xVmhanYiV0+dOdTx7PAZkw==") }
{ "_id" : { "Part1" : 3, "Part2" : 8 }, "SomeValue" : BinData(3,"5NNdVzErt0qephmCMRR1nQ==") }
{ "_id" : { "Part1" : 3, "Part2" : 9 }, "SomeValue" : BinData(3,"mhTiJoHGKkCPUeglCfLUoQ==") }
现在,当我运行一个查询返回的所有文件其中“Part1”> = 1和“Part1”< = 3,我应该得到所有9个文档,但mongo只返回6个文档(所有带{“Part1”:3 ...}的文档都被跳过)
db.DocumentWithCompoundKeyCollection.find({ “_id”:{ “$ GTE”:{ “第1部分”:1}, “$ LTE”:{ “第1部分”:3}}})
{ "_id" : { "Part1" : 1, "Part2" : 1 }, "SomeValue" : BinData(3,"B8+yWvTV4kS/u3e6Cv8Kcw==") }
{ "_id" : { "Part1" : 1, "Part2" : 2 }, "SomeValue" : BinData(3,"eLS1ONAoGUawW+v+vQdFDQ==") }
{ "_id" : { "Part1" : 1, "Part2" : 3 }, "SomeValue" : BinData(3,"m7WsIyInIEmsgWUMcsJPAw==") }
{ "_id" : { "Part1" : 2, "Part2" : 4 }, "SomeValue" : BinData(3,"z7/2j0g4AUikqS5K1TzZig==") }
{ "_id" : { "Part1" : 2, "Part2" : 5 }, "SomeValue" : BinData(3,"WudfqGYE8U+YwWe3Q0qL1w==") }
{ "_id" : { "Part1" : 2, "Part2" : 6 }, "SomeValue" : BinData(3,"B60SpSmXdUGn6AJDu1JIzg==") }
添加.explain()按预期返回正确的indexBounds,为什么最后3个文档没有被返回?
索引图
"winningPlan" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"_id" : {
"$lte" : {
"Part1" : 3
}
}
},
{
"_id" : {
"$gte" : {
"Part1" : 1
}
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"_id" : 1
},
"indexName" : "_id_",
"isMultiKey" : false,
"isUnique" : true,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 1,
"direction" : "forward",
"indexBounds" : {
"_id" : [
"[{ Part1: 1.0 }, { Part1: 3.0 }]"
]
}
}
},
感谢andresk但不幸的是我的代码是用另一种模块,它是依赖在这个模式和查询模式(所以我不能改变它)。 –