elastic/elasticsearch

CompletionSuggester can return partial information (no _id and _score)

Open

#32,467 opened on Jul 30, 2018

View on GitHub
 (7 comments) (0 reactions) (0 assignees)Java (25,882 forks)batch import
:Search Relevance/Suggesters>bugTeam:Search Relevancehelp wantedpriority:normal

Repository metrics

Stars
 (76,700 stars)
PR merge metrics
 (Avg merge 2d) (1,000 merged PRs in 30d)

Description

We are seeing this behavior from times to times, we see a spike on invalid responses returned by the completion suggester: the options returned may be "partial". By partial response I mean that the individual hits are not provided with the usual information retrieved during the fetch_phase.

In this case only text seems to be available, _id and _score are not populated.

I'm almost sure that this happens only when a node was dropped from the cluster or during a rolling restart.

Looking at the code this behavior seems to line-up with a TODO comment in SearchPhaseController.java where a failure during the fetch phase may produce this inconsistency.

Contributor guide

Research direction
Trace the fetch phase in SearchPhaseController.java to understand why id and score are missing when a node is dropped or during rolling restart. Identify the condition that causes partial response and ensure that all required fields are populated.
Tech stack
java
Domain
backendapi
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.
1-3 hours
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.
Clear
Prerequisites
JavaGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60