MongoDB 允许磁盘使用不工作..

Question

专家。

我是 MongoDB 的新手，但我知道的足够让我自己陷入困境。例如:

db.test.aggregate(
[
    {$group: {_id: {email: "$email", gender: "$gender"}, cnt: {$sum: 1}}}, 
    {$group: {_id: "$_id.email", cnt: {$sum: 1}}}, 
    {$match: {cnt: 2}}
], 
    {allowDiskUse : true}
)

无论我尝试什么变体，我都会收到相同的错误(“Pass allowDiskUse:true to opt in”):

Error("Printing Stack Trace")@:0 ()@src/mongo/shell/utils.js:37 ([object Array],[object Object])@src/mongo/shell/collection.js:866 @(shell):7

uncaught exception: aggregate failed: { "errmsg" : "exception: Received error in response from mongo1.mscnet.com:27017: { $err: \"Exceeded memory limit for $group, but didn't allow external sort. Pass allowDiskUse:true to opt in.\", code: 16945 }", "code" : 16945, "ok" : 0 }

仅供引用:我使用的是 Mongo 2.6

Answer 1

请在运行命令中使用聚合查询，它将允许使用allowDiskUse标签。

db.runCommand(
   { aggregate: "test",
     pipeline: [
                {$group: {_id: {email: "$email", gender: "$gender"}, cnt: {$sum: 1}}}, 
                {$group: {_id: "$_id.email", cnt: {$sum: 1}}}, 
                {$match: {cnt: 2}}
               ],
     allowDiskUse: true
   }
)