Which of the following metrics indicates the performance of search requests in Azure Cognitive Search?

The performance of search requests in Azure Cognitive Search can indeed be indicated by the percentage of throttled queries. This metric provides insight into how well the search service is managing the incoming load. Throttling occurs when the service limits the number of queries processed simultaneously due to resource constraints. A high percentage of throttled queries could indicate that the service is under stress or that the workload exceeds the allocated limits, which can adversely affect user experience and suggests a need for optimization or scaling.

Other metrics like the count of documents processed, number of errors per indexer, and average skill execution time provide valuable information about the infrastructure and functioning of the service but do not directly measure the performance of the search requests themselves. The count of documents processed reflects data ingestion rather than real-time query performance. The number of errors per indexer pertains to the data indexing process instead of search execution. Average skill execution time relates to the processing of data during enrichment but does not assess how effectively or quickly search requests are resolved. Therefore, the percentage of throttled queries is the most relevant metric for evaluating the performance of search requests in Azure Cognitive Search.