fix(vector): re-sync a note's vectors by replacing them; roll back a failed insert (#68)

The vectors table is a vec0 virtual table, where INSERT OR REPLACE does not replace, so syncing a note that already had vectors failed with a UNIQUE constraint error and the edit never reached the index. AddDocuments also shadowed err inside its loop, so a failed insert left the write transaction open and later writes failed with 'database is locked'.

Add Client.ReplaceDocuments (delete and insert in one transaction) and use it from SyncObservation and SyncSummary. The shared write function has a named result, so every failed return rolls back. Fixes #66.

Co-authored-by: Claude Sonnet 5.5 <[email protected]>

internal/vector/sqlitevec/client.go

@@ -139,9 +139,22 @@ func NewClient(cfg Config, embedSvc *embedding.Service) (*Client, error) {
 	return c, nil
 }
 
-// AddDocuments adds documents with their embeddings to the vector store.
+// AddDocuments embeds the documents and inserts them. A document whose ID already exists is an error (the vec0
+// table does not replace on insert); use ReplaceDocuments to write the documents of a note that may have some.
 func (c *Client) AddDocuments(ctx context.Context, docs []Document) error {
-	if len(docs) == 0 {
+	return c.writeDocuments(ctx, docs, "", 0)
+}
+
+// ReplaceDocuments writes the documents of one note (observation, summary, ...) in place of the ones it had: the old
+// documents are deleted and the new ones inserted in one transaction, so an edit that removes a fact leaves no stale
+// document behind and a failure leaves the old ones untouched. docs may be empty, which only deletes.
+func (c *Client) ReplaceDocuments(ctx context.Context, docType string, sqliteID int64, docs []Document) error {
+	return c.writeDocuments(ctx, docs, docType, sqliteID)
+}
+
+// writeDocuments inserts docs; when docType is not empty it first deletes every document of that note.
+func (c *Client) writeDocuments(ctx context.Context, docs []Document, docType string, sqliteID int64) (err error) {
+	if len(docs) == 0 && docType == "" {
 		return nil
 	}
 
@@ -154,9 +167,11 @@ func (c *Client) AddDocuments(ctx context.Context, docs []Document) error {
 	// Compute embeddings OUTSIDE the write lock for better concurrency.
 	// Embedding is ONNX inference (slow, mutex-protected internally) — holding
 	// writeMu during inference blocks all concurrent writes and reads.
-	embeddings, err := c.embedSvc.EmbedBatchWithContext(ctx, texts)
-	if err != nil {
-		return fmt.Errorf("generate embeddings: %w", err)
+	var embeddings [][]float32
+	if len(texts) > 0 {
+		if embeddings, err = c.embedSvc.EmbedBatchWithContext(ctx, texts); err != nil {
+			return fmt.Errorf("generate embeddings: %w", err)
+		}
 	}
 
 	// Acquire write lock for DB operations only
@@ -165,7 +180,7 @@ func (c *Client) AddDocuments(ctx context.Context, docs []Document) error {
 
 	// Insert into vectors table with model version tracking
 	const insertQuery = `
-		INSERT OR REPLACE INTO vectors (doc_id, embedding, sqlite_id, doc_type, field_type, project, scope, model_version)
+		INSERT INTO vectors (doc_id, embedding, sqlite_id, doc_type, field_type, project, scope, model_version)
 		VALUES (?, ?, ?, ?, ?, ?, ?, ?)
 	`
 
@@ -176,6 +191,8 @@ func (c *Client) AddDocuments(ctx context.Context, docs []Document) error {
 	if err != nil {
 		return fmt.Errorf("begin transaction: %w", err)
 	}
+	// err is the named result, so every failed return below reaches this and the write lock is released. (A shadowed
+	// err in the loop once left the transaction open, and the database locked, after a failed insert.)
 	defer func() {
 		if err != nil {
 			if rbErr := tx.Rollback(); rbErr != nil {
@@ -185,6 +202,12 @@ func (c *Client) AddDocuments(ctx context.Context, docs []Document) error {
 		}
 	}()
 
+	if docType != "" {
+		if _, err = tx.ExecContext(ctx, `DELETE FROM vectors WHERE doc_type = ? AND sqlite_id = ?`, docType, sqliteID); err != nil {
+			return fmt.Errorf("delete old documents: %w", err)
+		}
+	}
+
 	stmt, err := tx.PrepareContext(ctx, insertQuery)
 	if err != nil {
 		return fmt.Errorf("prepare statement: %w", err)
@@ -193,29 +216,28 @@ func (c *Client) AddDocuments(ctx context.Context, docs []Document) error {
 
 	for i, doc := range docs {
 		// Serialize embedding to blob format
-		embBlob, err := sqlite_vec.SerializeFloat32(embeddings[i])
-		if err != nil {
+		var embBlob []byte
+		if embBlob, err = sqlite_vec.SerializeFloat32(embeddings[i]); err != nil {
 			return fmt.Errorf("serialize embedding for %s: %w", doc.ID, err)
 		}
 
 		// Extract metadata
-		sqliteID, _ := doc.Metadata["sqlite_id"].(int64)
-		docType, _ := doc.Metadata["doc_type"].(string)
+		docSQLiteID, _ := doc.Metadata["sqlite_id"].(int64)
+		docDocType, _ := doc.Metadata["doc_type"].(string)
 		fieldType, _ := doc.Metadata["field_type"].(string)
 		project, _ := doc.Metadata["project"].(string)
 		scope, _ := doc.Metadata["scope"].(string)
 
-		_, err = stmt.ExecContext(ctx,
+		if _, err = stmt.ExecContext(ctx,
 			doc.ID,
 			embBlob,
-			sqliteID,
-			docType,
+			docSQLiteID,
+			docDocType,
 			fieldType,
 			project,
 			scope,
 			modelVersion,
-		)
-		if err != nil {
+		); err != nil {
 			return fmt.Errorf("insert document %s: %w", doc.ID, err)
 		}
 	}