解决MongoDB 排序超过内存限制的问题

> db.bigdata.aggregate( {$group : {_id : "$range", total : { $sum : 1 }}}, {$sort : {total : -1}});#... aggregate failed at Error (<anonymous>) 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 }

db.bigdata.aggregate([ {$group : {_id : "$range", total : { $sum : 1 }}}, {$sort : {total : -1}}], {allowDiskUse: true});