Splunk Enterprise Search Optimization documentation consistently emphasizes that filtering data as early as possible in the search pipeline is the most effective way to improve search performance. The base search (the part before the first pipe |) determines the volume of raw events Splunk retrieves from the indexers. Therefore, by applying restrictive conditions early—such as time ranges, indexed fields, and metadata filters—you can drastically reduce the number of events that need to be fetched and processed downstream.

The best practice is to use indexed field filters (e.g., index=security sourcetype=syslog host=server01) combined with search or where clauses at the start of the query. This minimizes unnecessary data movement between indexers and the search head, improving both search speed and system efficiency.

Using non-streaming commands early (Option C) can degrade performance because they require full result sets before producing output. Likewise, focusing solely on shortening queries (Option A) or excessive use of the not operator (Option D) does not guarantee efficiency, as both may still process large datasets.

Filtering early leverages Splunk’s distributed search architecture to limit data at the indexer level, reducing processing load and network transfer.

References (Splunk Enterprise Documentation):

• Search Performance Tuning and Optimization Guide

• Best Practices for Writing Efficient SPL Queries

• Understanding Streaming and Non-Streaming Commands

• Search Job Inspector: Analyzing Execution Costs