What Can I Do If the Query Speed Is Slow in Full-Text Retrieval Scenarios?

Symptom

The query speed is slow when the full-text retrieval is performed to query all indexes and fields provided.

Cause Analysis

Analysis on the cluster status shows that the number of indexes and shards is large, the planning is improper, and the number of index shards is set improperly.

After the query of slow logs, it is found that a large number of results need to be merged in the fetch phase. As a result, the query takes a long time.

Solution

Disable the swap memory, plan the number of index segments again, and combine index segments periodically to reduce the number of cluster segments.