elastic/elasticsearch

Phrase suggester with suggest_mode: "missing" across multiple indexes yields suggestions when results exist in one index

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#7472 opened on Aug 27, 2014

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 (17 comments) (1 reaction) (0 assignees)Java (76,700 stars) (25,882 forks)batch import
:Search Relevance/Suggesters>enhancementTeam:Search Relevancegood first issuehelp wanted

Description

I have found a few odd cases where the phrase suggester with suggest_mode: "missing" generates a suggestion even though the query returns results. I am querying across two indexes but the query term only exists in one of the indexes. I get the search results I expect, but I do not expect to get a suggestion.

I am trying to come up with a curl recreation but I haven't been able to reproduce it yet in a smaller corpus.

I believe what is happening is that the phrase suggestions are getting merged together in the same way the query results are merged together across multiple indexes. If I have query results from test_1 and no results from test_2, then I expect to see results from test_1. But if I have a suggestion from test_1 and no suggestion from test_2 (due to suggest_mode: "missing"), I do not expect to see a suggestion.

Contributor guide

Tech stack
javarest api
Domain
searchbackend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
understanding of Elasticsearch phrase suggesterknowledge of suggest mode 'missing'familiarity with multi index search merging
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
The issue describes a bug where the phrase suggester with suggest mode 'missing' produces suggestions even when results exist in one index. The root cause likely lies in how suggest results are merged across multiple indexes. To investigate, examine the suggest phase merging logic in Elasticsearch's transport or search action classes. Look at existing comments for potential reproduction steps and test cases. Focus on the ShardSuggestStep or similar components that handle per shard suggestion merging.