MongoDB 允许磁盘使用不起作用..
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MongoDB allowDiskUse not working..
提问by Eyal Zinder
Experts.
专家。
I'm new to MongoDB, but know enough to get my self in trouble.. case in point:
我是 MongoDB 的新手，但知道的足以让我自己陷入困境.. 举个例子：
db.test.aggregate(
[
{$group: {_id: {email: "$email", gender: "$gender"}, cnt: {$sum: 1}}},
{$group: {_id: "$_id.email", cnt: {$sum: 1}}},
{$match: {cnt: 2}}
],
{allowDiskUse : true}
)
and no matter what variations I try, I keep getting the same error ("Pass allowDiskUse:true to opt in"):
无论我尝试什么变化，我都会收到相同的错误（“通过 allowDiskUse:true 选择加入”）：
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 }
Error("打印堆栈跟踪")@:0 ()@src/mongo/shell/utils.js:37 ([object Array],[object Object])@src/mongo/shell/collection.js:866 @(外壳）：7
未捕获的异常：聚合失败：{“errmsg”：“异常：从 mongo1.mscnet.com 收到错误响应：27017：{ $err：\”超出了 $group 的内存限制，但不允许外部排序。通过 allowDiskUse:true 选择加入。\", code: 16945 }", "code" : 16945, "ok" : 0 }
FYI: I'm using Mongo 2.6
仅供参考：我正在使用 Mongo 2.6
回答by Dineshaws
Please use aggregate query in run command,it will allow to use allowDiskUse tag.
请在运行命令中使用聚合查询，它将允许使用 allowDiskUse 标签。
db.runCommand(
{ aggregate: "test",
pipeline: [
{$group: {_id: {email: "$email", gender: "$gender"}, cnt: {$sum: 1}}},
{$group: {_id: "$_id.email", cnt: {$sum: 1}}},
{$match: {cnt: 2}}
],
allowDiskUse: true
}
)
回答by MAULIK MODI
Try writing like this,
试试这样写
db.stocks.aggregate([
{ $project : { cusip: 1, date: 1, price: 1, _id: 0 } },
{ $sort : { cusip : 1, date: 1 } }
],
{
allowDiskUse: true
}
);
And One more thing,
Your error about maximum document size is inherent to Mongo. Mongo can never return a document (or array thereof) larger than 16 megabytes. I can't tell you why because you didn't mention anything about data size, but it probably means that the document you're building as an end result is too large. Try decreasing the $limit parameter, maybe? Start by setting it to 1, run a test, then increase it and look at how big the result gets when you do that
还有一件事，
您关于最大文档大小的错误是 Mongo 固有的。Mongo 永远不能返回大于 16 兆字节的文档（或其数组）。我无法告诉您原因，因为您没有提到任何有关数据大小的内容，但这可能意味着您作为最终结果构建的文档太大。尝试减少 $limit 参数，也许？首先将它设置为 1，运行一个测试，然后增加它并看看当你这样做时结果有多大
回答by pushpak
If you are working with m10 or laterversion of MongoDB Atlas, below is the fix for {allowDiskUse: true};If you are accessing data from application via mongoose then, it should be syntax as function. For example:
如果您正在使用m10 或更高版本的 MongoDB Atlas，以下是修复{allowDiskUse: true};如果您通过 mongoose 从应用程序访问数据，则它应该是语法即函数。例如：
MongoDb Query:
MongoDb 查询：
db.collection.user.aggregate([], {allowDiskUse: true})
With Mongoose:
猫鼬：
User.aggregate([]).allowDiskUse(true);
This will resolve error from application :)
这将解决应用程序中的错误:)
