Which argument to the | tstats command restricts the search to summarized data only?

The argument that restricts the search to summarized data only is "summariesonly=t." When you use this argument in the | tstats command, it ensures that the search focuses solely on the pre-computed summary data rather than searching through raw events. This is particularly beneficial when you want to improve performance and query speed, as summarized data is optimized for quick retrieval.

The use of summariesonly=t tells Splunk that you want to limit your results to only those that are accessible via the summary indexes, which contain the processed data from your larger dataset. This approach helps in analyzing the overall trends or patterns without the overhead of querying raw logs, thus facilitating faster data analysis in scenarios like reporting and dashboard creation.

Having a thorough understanding of this command and its arguments is essential for efficiently using Splunk, particularly when dealing with large datasets that can slow down queries if not approached correctly.