Final answer:
The two major functions of the $match stage are filtering data according to specific conditions and reducing the size of the dataset for improved efficiency and performance in data processing pipelines.
Step-by-step explanation:
The two major functions of the $match stage in data processing, particularly when using aggregation frameworks such as MongoDB, are to filter data and to reduce the size of a dataset. This essential stage in the pipeline allows you to specify conditions that dictate which documents (or rows of data) should pass through to the next stage of the aggregation pipeline. By matching documents against those conditions, it effectively "prunes" the data, ensuring that only relevant documents are included in subsequent stages, thus improving the efficiency of the data processing.
Furthermore, the $match stage can also promote better performance since operations later in the pipeline will have fewer documents to process. By removing unwarranted documents as early as possible, it minimizes the resources required for processing. As such, it plays a critical role in query optimization and resource utilization.