A bug in MONGODB 2.6.8 [Assertion:13548:bufbuilder attempted to grow () to 134217728 bytes, past the]

Environment: mongoDB2.6.8 Cluster,
In the afternoon suddenly found 4 from the node, hanging 3, all appear the following prompts:

2016-03-11t16:53:02.483+0800 [conn312773] Assertion:13548:bufbuilder attempted to grow () to 134217728 bytes, past the 64M B limit.

After analysis, [conn312773] Connect the previous query is all statistical analysis class query, followed by the development department to confirm.
They think they have a problem with the following query.

Less commonly used here is: item:{$push: "$ $ROOT"}
This function is this: the query to the data, the list of all the data in $push way to return to the item,
The advantage of this is that in a page, there are summary data, followed by a corresponding detail.
The disadvantage is that if the detail value is too large, it triggers the bug above. In the official bug description, the version 2.4.6 is resolved. But in 2.6.8, we still
It is a reason to encounter, and may be rarely used.


Db.getcollection (' pinfo '). Aggregate ([
{
$match: {mid:86}
},
{
$group: {
_id: {PID: "$PID"},
Sumcount: {$sum: 1},
item:{$push: "$ $ROOT"}
}
}
])


Our solution:
Change the value of $push in item from total record to only return a few fields (as little as possible, and do not return subdocuments and arrays, because these two types are difficult to foresee how large)
The query condition is optimized to the minimum, and only a small amount of data is queried at a time. Thus reducing the amount of data returned.