tsidx retention policy
The tsidx retention policy determines how long the indexer retains the tsidx files that it uses to search efficiently and quickly across its data. By default, the indexer retains the tsidx files for all its indexed data for as long as it retains the data itself. By adjusting the policy, you can set the optimal trade-off between storage costs and search performance.
For more information
In Managing Indexers and Clusters of Indexers: