[LUCENE-4539] DocValues impls should read all headers up-front instead of per-directsource

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: core/index
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Robert Muir
• Created: 05/Nov/12 14:01
• Updated: 28/Aug/22 13:31

Description

Currently, when DocValues opens, it just opens files. it doesnt read codec headers etc.

Instead we read these every single time a directsource opens.

I think it should work like PostingsReaders: e.g. the PackedInts impl would read its versioning info and codec headers and creating a new Direct impl should be a IndexInput.clone() + getDirectReaderNoHeader().

Today its much more costly.