# Lucene 9.10.0 misc API

# Misc Tools

The misc package has various tools for splitting/merging indices, changing norms, finding high freq terms, and others.

## DirectIODirectory

`DirectIODirectory` is a Directory implementation that bypasses the OS's buffer cache (using direct IO) for any IndexInput and IndexOutput used during merging of segments larger than a specified size (default 10 MB). This avoids evicting hot pages that are still in-use for searching, keeping search more responsive while large merges run.

See this blog post for details.

Packages
Package | Description
--- | ---
org.apache.lucene.misc | Miscellaneous Lucene utilities that don't really fit anywhere else.
org.apache.lucene.misc.document | Misc extensions of the Document/Field API.
org.apache.lucene.misc.index | Misc index tools and index support.
org.apache.lucene.misc.search | Misc search implementations.
org.apache.lucene.misc.store | Misc Directory implementations.
org.apache.lucene.misc.util | Memory Tracker interface which allows defining custom collector level memory trackers
org.apache.lucene.misc.util.fst | Misc FST classes.