[LUCENE-9541] Ensure sub-iterators of ConjunctionDISI are on the same document

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Mayya Sharipova
• Created: 23/Sep/20 13:44
• Updated: 28/Aug/22 16:08

Description

Not completely sure if this is a bug.

BitSetConjuctionDISI advances based on its lead  – DocIdSetIterator iterator, and doesn't consider that its another component – BitSetIterator may have already advanced passed a certain doc. This may result in duplicate documents.

For example if BitSetConjuctionDISI  disi is composed of DocIdSetIterator a of docs  [0,1] and BitSetIterator b of docs [0,1].  Doing `b.nextDoc()` we are collecting doc0,  doing `disi.nextDoc` we again  collecting the same doc0.

It seems that other conjunction iterators don't have this behaviour, if we are advancing any of their component pass a certain document, the whole conjunction iterator will also be advanced pass this document. 

 

This behaviour was exposed in this PR. 

 

Issue Links

• links to: GitHub Pull Request #1937