这是我的查询
db.getCollection("images").find({
"$and": [
{ "text": { "$ne": null } },
{ "text": { "$ne": "" } },
],
"width":"3120"
})
和explain结果：
{
"queryPlanner" : {
"plannerVersion" : 1.0,
"namespace" : "mhxy.images",
"indexFilterSet" : false,
"parsedQuery" : {
"$and" : [
{
"width" : {
"$eq" : "3120"
}
},
{
"text" : {
"$not" : {
"$eq" : null
}
}
},
{
"text" : {
"$not" : {
"$eq" : ""
}
}
}
]
},
"queryHash" : "7DCCCA85",
"planCacheKey" : "5D3F5173",
"winningPlan" : {
"stage" : "FETCH",
"filter" : {
"$and" : [
{
"text" : {
"$not" : {
"$eq" : null
}
}
},
{
"text" : {
"$not" : {
"$eq" : ""
}
}
}
]
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"width" : 1.0
},
"indexName" : "idx_width",
"isMultiKey" : false,
"multiKeyPaths" : {
"width" : [
]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2.0,
"direction" : "forward",
"indexBounds" : {
"width" : [
"[\"3120\", \"3120\"]"
]
}
}
},
"rejectedPlans" : [
{
"stage" : "FETCH",
"filter" : {
"width" : {
"$eq" : "3120"
}
},
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"text" : 1.0
},
"indexName" : "idx_text",
"isMultiKey" : false,
"multiKeyPaths" : {
"text" : [
]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2.0,
"direction" : "forward",
"indexBounds" : {
"text" : [
"[MinKey, undefined)",
"(null, \"\")",
"(\"\", MaxKey]"
]
}
}
},
{
"stage" : "FETCH",
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"text" : 1.0,
"width" : 1.0
},
"indexName" : "idx_text_width",
"isMultiKey" : false,
"multiKeyPaths" : {
"text" : [
],
"width" : [
]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2.0,
"direction" : "forward",
"indexBounds" : {
"text" : [
"[MinKey, undefined)",
"(null, \"\")",
"(\"\", MaxKey]"
],
"width" : [
"[\"3120\", \"3120\"]"
]
}
}
}
]
},
"serverInfo" : {
"host" : "...",
"port" : 27017.0,
"version" : "4.2.1",
"gitVersion" : "edf6d45851c0b9ee15548f0f847df141764a317e"
},
"ok" : 1.0
}
此集合的大小超过13Gb。并记录如下：
{
"_id" : ObjectId("5dbac8665ef144e92017e190"),
"o_img" : BinData(0, "/9j/4AAQSkZJRgABAQAAAQABAAD/4gIo.. 1103798 more bytes"),
"c_img" : BinData(0, "/9j/4AAQSkZJRgABAQAAAQABAAD/4gIo.. 81058 more bytes"),
"date" : ISODate("2019-10-31T11:41:26.238+0000"),
"text" : "....",
"correct_text" : "....",
"bit" : "119667",
"width" : "3120",
"height" : "1440"
}
似乎查询过程的每一步都触及索引。
但是查询至少需要20秒。
此外，我发现mongodb占用了计算机内存的90％以上。
我的计算机内存是否太小？我可以使mongodb不能将二进制数据加载到内存中吗？