Find no row, not an error, for a missing rowid on rescore and DiskANN columns

sqlite-vec.c

@@ -4042,6 +4042,21 @@ int vec0_get_vector_data(vec0_vtab *pVtab, i64 rowid, int vector_column_idx,
                          void **outVector, int *outVectorSize) {
   vec0_vtab *p = pVtab;
   int rc, brc;
+  i64 chunk_id;
+  i64 chunk_offset;
+  assert((vector_column_idx >= 0) &&
+         (vector_column_idx < pVtab->numVectorColumns));
+
+  // Every index type registers its rows in _rowids, so a rowid with no
+  // position there is no row, whichever table holds the column's vectors.
+  rc = vec0_get_chunk_position(pVtab, rowid, NULL, &chunk_id, &chunk_offset);
+  if (rc == SQLITE_EMPTY) {
+    vtab_set_error(&pVtab->base, "Could not find a row with rowid %lld", rowid);
+    return rc;
+  }
+  if (rc != SQLITE_OK) {
+    return rc;
+  }
 
 #if SQLITE_VEC_ENABLE_DISKANN
   // DiskANN fast path: read from _vectors table
@@ -4061,9 +4076,6 @@ int vec0_get_vector_data(vec0_vtab *pVtab, i64 rowid, int vector_column_idx,
   }
 #endif
 
-  i64 chunk_id;
-  i64 chunk_offset;
-
 #if SQLITE_VEC_EXPERIMENTAL_IVF_ENABLE
   // IVF-indexed columns store vectors in _ivf_cells, not _vector_chunks
   if (p->vector_columns[vector_column_idx].index_type == VEC0_INDEX_TYPE_IVF) {
@@ -4074,8 +4086,6 @@ int vec0_get_vector_data(vec0_vtab *pVtab, i64 rowid, int vector_column_idx,
   void *buf = NULL;
   int blobOffset;
   sqlite3_blob *vectorBlob = NULL;
-  assert((vector_column_idx >= 0) &&
-         (vector_column_idx < pVtab->numVectorColumns));
 
 #if SQLITE_VEC_ENABLE_RESCORE
   // Rescore columns store float vectors in _rescore_vectors (rowid-keyed)
@@ -4112,15 +4122,6 @@ int vec0_get_vector_data(vec0_vtab *pVtab, i64 rowid, int vector_column_idx,
   }
 #endif /* SQLITE_VEC_ENABLE_RESCORE */
 
-  rc = vec0_get_chunk_position(pVtab, rowid, NULL, &chunk_id, &chunk_offset);
-  if (rc == SQLITE_EMPTY) {
-    vtab_set_error(&pVtab->base, "Could not find a row with rowid %lld", rowid);
-    goto cleanup;
-  }
-  if (rc != SQLITE_OK) {
-    goto cleanup;
-  }
-
   rc = sqlite3_blob_open(p->db, p->schemaName,
                          p->shadowVectorChunksNames[vector_column_idx],
                          "vectors", chunk_id, 0, &vectorBlob);

tests/test-diskann.py

@@ -324,6 +324,26 @@ def test_diskann_delete_single(db):
     assert db.execute("SELECT count(*) FROM t_diskann_nodes00").fetchone()[0] == 2
 
 
+def test_diskann_point_query_missing_rowid(db):
+    """SELECT by a rowid the table does not hold returns no rows."""
+    db.execute("""
+        CREATE VIRTUAL TABLE t USING vec0(
+            emb float[8] INDEXED BY diskann(neighbor_quantizer=binary, n_neighbors=8)
+        )
+    """)
+    for i in range(1, 3):
+        db.execute(
+            "INSERT INTO t(rowid, emb) VALUES (?, ?)",
+            [i, _f32([float(i)] * 8)],
+        )
+    db.execute("DELETE FROM t WHERE rowid = 2")
+
+    rows = db.execute("SELECT rowid FROM t WHERE rowid = 1").fetchall()
+    assert [r[0] for r in rows] == [1]
+    assert db.execute("SELECT rowid FROM t WHERE rowid = 2").fetchall() == []
+    assert db.execute("SELECT rowid FROM t WHERE rowid = 999").fetchall() == []
+
+
 def test_diskann_delete_no_stale_references(db):
     """After delete, no node should reference the deleted rowid."""
     db.execute("""

tests/test-ivf.py

@@ -167,6 +167,21 @@ def test_ivf_delete_flat_mode(db):
     assert db.execute("SELECT count(*) FROM t_ivf_rowid_map00").fetchone()[0] == 1
 
 
+def test_ivf_point_query_missing_rowid(db):
+    """SELECT by a rowid the table does not hold returns no rows."""
+    db.execute(
+        "CREATE VIRTUAL TABLE t USING vec0(v float[4] indexed by ivf(nlist=4))"
+    )
+    db.execute("INSERT INTO t(rowid, v) VALUES (1, ?)", [_f32([1, 2, 3, 4])])
+    db.execute("INSERT INTO t(rowid, v) VALUES (2, ?)", [_f32([5, 6, 7, 8])])
+    db.execute("DELETE FROM t WHERE rowid = 2")
+
+    rows = db.execute("SELECT rowid FROM t WHERE rowid = 1").fetchall()
+    assert [r[0] for r in rows] == [1]
+    assert db.execute("SELECT rowid FROM t WHERE rowid = 2").fetchall() == []
+    assert db.execute("SELECT rowid FROM t WHERE rowid = 999").fetchall() == []
+
+
 # ============================================================================
 # KNN flat mode tests
 # ============================================================================

tests/test-rescore.py

@@ -261,6 +261,26 @@ def test_point_query_returns_float(db):
         assert abs(a - b) < 1e-6
 
 
+@pytest.mark.parametrize("quantizer", ["bit", "int8"])
+def test_point_query_missing_rowid(db, quantizer):
+    """SELECT by a rowid the table does not hold returns no rows."""
+    db.execute(
+        "CREATE VIRTUAL TABLE t USING vec0("
+        f"  embedding float[8] indexed by rescore(quantizer={quantizer})"
+        ")"
+    )
+    for rowid in (1, 2):
+        db.execute(
+            "INSERT INTO t(rowid, embedding) VALUES (?, ?)",
+            [rowid, float_vec([0.1 * rowid] * 8)],
+        )
+    db.execute("DELETE FROM t WHERE rowid = 2")
+    rows = db.execute("SELECT rowid FROM t WHERE rowid = 1").fetchall()
+    assert [r["rowid"] for r in rows] == [1]
+    assert db.execute("SELECT rowid FROM t WHERE rowid = 2").fetchall() == []
+    assert db.execute("SELECT rowid FROM t WHERE rowid = 999").fetchall() == []
+
+
 # ============================================================================
 # KNN tests
 # ============================================================================