The most efficient search is the one that retrieves the least amount of data from the indexes and performs the least amount of processing on the search head. Among the four options, the most efficient search is D, (index=www) OR (index=sales) | search (index=www status=200 uri=/cart/checkout) OR (index=sales) | stats count, sum(revenue) as total_revenue by session_id | table total_revenue session_id. This is because:
It uses a base search to limit the data to only two indexes, www and sales, which are relevant for the query.
It uses a subsearch to further filter the data by status and uri for the www index, and by index for the sales index.
It uses a stats command to aggregate the data by session_id and calculate the count and total revenue.
It uses a table command to display only the required fields.
The other options are less efficient for various reasons:
Option A uses an append command, which is expensive and can cause memory issues. It also does not filter the data by status and uri for the www index, which can retrieve more data than needed.
Option B uses a boolean OR operator, which can be slower than a subsearch. It also does not filter the data by status and uri for the www index, which can retrieve more data than needed.
Option C does not use a base search to limit the data to specific indexes, which can retrieve more data than needed. It also uses an append command, which is expensive and can cause memory issues.
Therefore, the correct answer is D, (index=www) OR (index=sales) | search (index=www status=200 uri=/cart/checkout) OR (index=sales) | stats count, sum(revenue) as total_revenue by session_id | table total_revenue session_id. References :=
Quick tips for optimization
About search optimization
The Secret to a Great Splunk Search
How to make efficient and fast searches
