Budget numeric MySQL wire parameters conservatively

Author: TonisOrmisson

src/openstatspec/sql/profiles.py

@@ -307,7 +307,9 @@ def statement_payload_bytes(
     size = 32
     for variable in variables:
         if variable.get("storage_kind") == "numeric":
-            size += 8
+            # PyMySQL serializes binary64 parameters as decimal wire text;
+            # the longest finite literal is 24 bytes (including its sign).
+            size += 24
         else:
             value = row.get(str(variable["physical_name"]), "")
             size += len(str(value).encode("utf-8")) + 8

tests/test_catalog_lifecycle.py

@@ -277,6 +277,19 @@ def test_bounded_batches_never_exceed_statement_payload_limit():
     assert batches == [rows[:2], rows[2:]]
 
 
+def test_bounded_batches_budget_numeric_pymysql_wire_literals():
+    variables = [{
+        "source_name": "value",
+        "physical_name": "value",
+        "storage_kind": "numeric",
+    }]
+    rows = [{"value": -1.7976931348623157e+308}] * 2
+
+    assert wide.statement_payload_bytes(rows[0], variables) == 56
+    assert list(_bounded_batches(rows, variables, 111)) == [[rows[0]], [rows[1]]]
+    assert list(_bounded_batches(rows, variables, 112)) == [rows]
+
+
 def test_duplicate_import_failure_preserves_existing_dataset(tmp_path):
     path = tmp_path / "duplicate.sqlite"
     database = f"sqlite:///{path}"