The FST index supports regex queries on text. Decreases on-disk index by 4-6 times.
Only supports regex queries
Only supported on stored or completed Pinot segments (no consuming segments).
Only supported on dictionary-encoded columns.
Works better for prefix queries
For more information on the FST construction and code, see Lucene documentation.
To enable the FST index on a dictionary-encoded column, include the following configuration:
The FST index generates one FST index file (.lucene.fst)
. If the inverted index is enabled, this is further able to take advantage of that.
For more information about enabling the FST index, see ways to enable indexes.