Solve the problem that MongoDB sorting exceeds the memory limit

Perform a large sort operation (such as aggregation) on the collection with the following error: (test version: MongoDB 3.0.6)

> db.bigdata.aggregate ({$group: {_ id: "$range", total: {$sum: 1}}, {$sort: {total:-1}}); #. Aggregate failed at Error () at doassert (src/mongo/shell/assert.js:11:14) #... Error: command failed: {"errmsg": "exception: Sort exceeded memory limit of 104857600 bytes, but did not opt in to external sorting. Aborting operation. Pass allowDiskUse:true to opt in.", "code": 16819, "ok": 0}

Solution method

Reference document: Memory Restrictions

In MongoDB, the maximum internal sort large memory limit is 100m, and if you perform a larger sort, you need to use the allowDiskUse option to write the data to a temporary file to sort.

Add the allowDiskUse option to the query statement:

Db.bigdata.aggregate ([{$group: {_ id: "$range", total: {$sum: 1}, {$sort: {total:-1}}], {allowDiskUse: true})

Summary

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