Answer
Large pipelines may spill to disk when memory is insufficient, drastically slowing performance.
Quick Answer
Aggregation pipelines that produce large intermediate results use memory. MongoDB limits aggregation memory to 100MB by default. If exceeded, the pipeline fails unless you add allowDiskUse: true (allows spilling to disk - slower). Optimize: add $match and $project early to reduce document size before expensive stages, use indexes in $match, avoid $unwind on large arrays early in the pipeline.
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
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Source: SugharaIQ