擅长:python、mysql、java
<p>您应该将<code>allowDiskUse</code>值设置为<code>true</code>。例如:</p>
<pre><code>db.books.aggregate( [
{ $group : { _id : "$author", books: { $push: "$title" } } },
{allowDiskUse:true}
] )
</code></pre>
<blockquote>
<p>Pipeline stages have a limit of 100 megabytes of RAM. If a stage
exceeds this limit, MongoDB will produce an error. To allow for the
handling of large datasets, use the allowDiskUse option to enable
aggregation pipeline stages to write data to temporary files.</p>
</blockquote>
<p>你可以阅读更多关于这个<a href="https://docs.mongodb.com/manual/core/aggregation-pipeline-limits/" rel="nofollow noreferrer">here</a>。在</p>