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Aggregation Mechanics

This section describes behaviors and limitations for the various aggregation modalities.

Aggregation Pipeline Optimization
Details the internal optimization of certain pipeline sequence.
Aggregation Pipeline Limits
Presents limitations on aggregation pipeline operations.
Aggregation Pipeline and Sharded Collections
Mechanics of aggregation pipeline operations on sharded collections.
Map-Reduce and Sharded Collections
Mechanics of map-reduce operation with sharded collections.
Map Reduce Concurrency
Details the locks taken during map-reduce operations.