According to Splunk best practices, which placement of the wildcard results in the most efficient search?

Question

Options

• Af*il
• B*fail
• Cfail*
• Dfail

• A
  10% (3)
• B
  7% (2)
• C
  79% (23)
• D
  3% (1)

Explanation

Placing the wildcard at the end of a term (fail*) is most efficient because Splunk's inverted index is organized lexicographically - it can quickly locate all indexed terms beginning with "fail" and return matches without a full scan. A leading wildcard (*fail) forces Splunk to evaluate every term in the index to find those ending in "fail", bypassing the index's sorting advantage entirely. A mid-term wildcard (f*il) is similarly problematic because the gap breaks the prefix lookup, again requiring a broad scan. Both-sided wildcards (*fail*) combine both penalties, making them the worst option for performance.

Memory tip: Think of the index like a phone book sorted by first name. Finding everyone named "Fail-something" is instant - you just open to "F." But finding everyone whose name ends in "fail" means reading every single page. Wildcards only help Splunk when they come after a known prefix.

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