The MongoDB Aggregation Framework | Chapter 6 - Aggregation Performance and Pipeline Quiz Answer
In this article i am gone to share MongoDB-University Course: The MongoDB Aggregation Framework | Chapter 6 - Aggregation Performance and Pipeline Quiz Answer with you..
Aggregation Performance
With regards to aggregation performance, which of the following are true?
- You can increase index usage by moving $match stages to the end of your pipeline
- When $limit and $sort are close together a very performant top-k sort can be performed
- Passing allowDiskUsage to your aggregation queries will seriously increase their performance
- Transforming data in a pipeline stage prevents us from using indexes in the stages that follow
Aggregation Pipeline on a Sharded Cluster
What operators will cause a merge stage on the primary shard for a database?
- $lookup
- $out
- $group
Pipeline Optimization - Part 2
Which of the following statements is/are true?
- The query in a $match stage can be entirely covered by an index
- The Aggregation Framework will automatically reorder stages in certain conditions
- The Aggregation Framework can automatically project fields if the shape of the final document is only dependent upon those fields in the input document.
- Causing a merge in a sharded deployment will cause all subsequent pipeline stages to be performed in the same location as the merge
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