Tencent/WeKnora · error

hit missing _source field

Error message

hit missing _source field

What it means

Elasticsearch v7 reindex guard: a search hit from the source index could not be decoded as a map containing a '_source' field, meaning the hit document is malformed or the index mapping changed; the per-hit processing aborts because required document fields cannot be read.

Source

Thrown at internal/application/repository/retriever/elasticsearch/v7/repository.go:1165

func (e *elasticsearchRepository) processSingleHit(ctx context.Context,
	hit interface{},
	sourceToTargetKBIDMap map[string]string,
	sourceToTargetChunkIDMap map[string]string,
	targetKnowledgeBaseID string,
) (*typesLocal.IndexInfo, []float32, error) {
	log := logger.GetLogger(ctx)

	hitMap, ok := hit.(map[string]interface{})
	if !ok {
		log.Warnf("[ElasticsearchV7] Invalid hit object format")
		return nil, nil, fmt.Errorf("invalid hit object format")
	}

	// Get document source
	sourceObj, ok := hitMap["_source"].(map[string]interface{})
	if !ok {
		log.Warnf("[ElasticsearchV7] Hit missing _source field")
		return nil, nil, fmt.Errorf("hit missing _source field")
	}

	// Get source ChunkID and corresponding target ChunkID
	sourceChunkID, ok := sourceObj["chunk_id"].(string)
	if !ok {
		log.Warnf("[ElasticsearchV7] Source index data missing chunk_id field")
		return nil, nil, fmt.Errorf("source index data missing chunk_id field")
	}

	targetChunkID, ok := sourceToTargetChunkIDMap[sourceChunkID]
	if !ok {
		log.Warnf("[ElasticsearchV7] Source chunk ID %s not found in mapping", sourceChunkID)
		return nil, nil, fmt.Errorf("source chunk ID %s not found in mapping", sourceChunkID)
	}

	// Get mapped target knowledge ID
	sourceKnowledgeID, ok := sourceObj["knowledge_id"].(string)
	if !ok {

View on GitHub (pinned to 988cbb0330)

Solutions

1. Inspect the raw hit JSON and source index mapping
2. Skip malformed hits with a warning if partial reindexing is acceptable
3. Verify the source index documents were written by a compatible version

When it happens

Trigger: Thrown at internal/application/repository/retriever/elasticsearch/v7/repository.go:1165 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of Tencent/WeKnora@988cbb0330 (2026-09-02). Data as JSON: /api/errors/6cb5e9f107677645. Report an issue: GitHub.