SQLite like API mode of chDB

.clang-tidy

@@ -27,6 +27,8 @@ Checks: [
   '-bugprone-not-null-terminated-result',
   '-bugprone-reserved-identifier', # useful but too slow, TODO retry when https://reviews.llvm.org/rG1c282052624f9d0bd273bde0b47b30c96699c6c7 is merged
   '-bugprone-unchecked-optional-access',
+  '-bugprone-crtp-constructor-accessibility',
+  '-bugprone-suspicious-stringview-data-usage',
 
   '-cert-dcl16-c',
   '-cert-dcl37-c',
@@ -36,6 +38,7 @@ Checks: [
   '-cert-msc51-cpp',
   '-cert-oop54-cpp',
   '-cert-oop57-cpp',
+  '-cert-err33-c', # Misreports on clang-19: it warns about all functions containing 'remove' in the name, not only about the standard library.
 
   '-clang-analyzer-optin.performance.Padding',
 
@@ -94,10 +97,12 @@ Checks: [
   '-modernize-pass-by-value',
   '-modernize-return-braced-init-list',
   '-modernize-use-auto',
+  '-modernize-use-constraints', # This is a good check, but clang-tidy crashes, see https://github.com/llvm/llvm-project/issues/91872
   '-modernize-use-default-member-init',
   '-modernize-use-emplace',
   '-modernize-use-nodiscard',
   '-modernize-use-trailing-return-type',
+  '-modernize-use-designated-initializers',
 
   '-performance-enum-size',
   '-performance-inefficient-string-concatenation',
@@ -121,7 +126,8 @@ Checks: [
   '-readability-magic-numbers',
   '-readability-named-parameter',
   '-readability-redundant-declaration',
-  '-readability-redundant-inline-specifier',
+  '-readability-redundant-inline-specifier', # useful but incompatible with __attribute((always_inline))__ (aka. ALWAYS_INLINE, base/base/defines.h).
+        # ALWAYS_INLINE only has an effect if combined with `inline`: https://godbolt.org/z/Eefd74qdM
   '-readability-redundant-member-init', # Useful but triggers another problem. Imagine a struct S with multiple String members. Structs are often instantiated via designated
         # initializer S s{.s1 = [...], .s2 = [...], [...]}. In this case, compiler warning `missing-field-initializers` requires to specify all members which are not in-struct
         # initialized (example: s1 in struct S { String s1; String s2{};}; is not in-struct initialized, therefore it must be specified at instantiation time). As explicitly
@@ -132,12 +138,7 @@ Checks: [
   '-readability-uppercase-literal-suffix',
   '-readability-use-anyofallof',
 
-  '-zircon-*',
-
-  # This is a good check, but clang-tidy crashes, see https://github.com/llvm/llvm-project/issues/91872
-  '-modernize-use-constraints',
-  # https://github.com/abseil/abseil-cpp/issues/1667
-  '-clang-analyzer-optin.core.EnumCastOutOfRange'
+  '-zircon-*'
 ]
 
 WarningsAsErrors: '*'
@@ -172,4 +173,4 @@ CheckOptions:
   performance-move-const-arg.CheckTriviallyCopyableMove: false
   # Workaround clang-tidy bug: https://github.com/llvm/llvm-project/issues/46097
   readability-identifier-naming.TypeTemplateParameterIgnoredRegexp: expr-type
-  cppcoreguidelines-avoid-do-while.IgnoreMacros: true
+  cppcoreguidelines-avoid-do-while.IgnoreMacros: true

.cursorignore

@@ -0,0 +1 @@
+contrib/

chdb/__init__.py

@@ -85,8 +85,10 @@ def query(sql, output_format="CSV", path="", udf_path=""):
 PyReader = _chdb.PyReader
 
 from . import dbapi, session, udf, utils  # noqa: E402
+from .state import connect  # noqa: E402
 
 __all__ = [
+    "_chdb",
     "PyReader",
     "ChdbError",
     "query",
@@ -99,4 +101,5 @@ def query(sql, output_format="CSV", path="", udf_path=""):
     "session",
     "udf",
     "utils",
+    "connect",
 ]

chdb/dbapi/connections.py

@@ -1,7 +1,7 @@
-import json
 from . import err
 from .cursors import Cursor
 from . import converters
+from ..state import sqlitelike as chdb_stateful
 
 DEBUG = False
 VERBOSE = False
@@ -10,152 +10,78 @@
 class Connection(object):
     """
     Representation of a connection with chdb.
-
-    The proper way to get an instance of this class is to call
-    connect().
-
-    Accepts several arguments:
-
-    :param cursorclass: Custom cursor class to use.
-    :param path: Optional folder path to store database files on disk.
-
-    See `Connection <https://www.python.org/dev/peps/pep-0249/#connection-objects>`_ in the
-    specification.
     """
 
-    _closed = False
-    _session = None
-
-    def __init__(self, cursorclass=Cursor, path=None):
-
-        self._resp = None
-
-        # 1. pre-process params in init
-        self.encoding = 'utf8'
-
-        self.cursorclass = cursorclass
-
-        self._result = None
+    def __init__(self, path=None):
+        self._closed = False
+        self.encoding = "utf8"
         self._affected_rows = 0
+        self._resp = None
 
-        self.connect(path)
+        # Initialize sqlitelike connection
+        connection_string = ":memory:" if path is None else f"file:{path}"
+        self._conn = chdb_stateful.Connection(connection_string)
 
-    def connect(self, path=None):
-        from chdb import session as chs
-        self._session = chs.Session(path)
-        self._closed = False
-        self._execute_command("select 1;")
-        self._read_query_result()
+        # Test connection with a simple query
+        cursor = self._conn.cursor()
+        cursor.execute("SELECT 1")
+        cursor.close()
 
     def close(self):
-        """
-        Send the quit message and close the socket.
-
-        See `Connection.close() <https://www.python.org/dev/peps/pep-0249/#Connection.close>`_
-        in the specification.
-
-        :raise Error: If the connection is already closed.
-        """
+        """Send the quit message and close the socket."""
         if self._closed:
             raise err.Error("Already closed")
         self._closed = True
-        self._session = None
+        self._conn.close()
 
     @property
     def open(self):
         """Return True if the connection is open"""
         return not self._closed
 
     def commit(self):
-        """
-        Commit changes to stable storage.
-
-        See `Connection.commit() <https://www.python.org/dev/peps/pep-0249/#commit>`_
-        in the specification.
-        """
-        return
+        """Commit changes to stable storage."""
+        # No-op for ClickHouse
+        pass
 
     def rollback(self):
-        """
-        Roll back the current transaction.
-
-        See `Connection.rollback() <https://www.python.org/dev/peps/pep-0249/#rollback>`_
-        in the specification.
-        """
-        return
+        """Roll back the current transaction."""
+        # No-op for ClickHouse
+        pass
 
     def cursor(self, cursor=None):
-        """
-        Create a new cursor to execute queries with.
-
-        :param cursor: The type of cursor to create; current only :py:class:`Cursor`
-            None means use Cursor.
-        """
+        """Create a new cursor to execute queries with."""
+        if self._closed:
+            raise err.Error("Connection closed")
         if cursor:
-            return cursor(self)
-        return self.cursorclass(self)
+            return Cursor(self)
+        return Cursor(self)
 
-    # The following methods are INTERNAL USE ONLY (called from Cursor)
-    def query(self, sql):
-        if isinstance(sql, str):
-            sql = sql.encode(self.encoding, 'surrogateescape')
-        self._execute_command(sql)
-        self._affected_rows = self._read_query_result()
-        return self._affected_rows
-
-    def _execute_command(self, sql):
-        """
-        :raise InterfaceError: If the connection is closed.
-        :raise ValueError: If no username was specified.
-        """
+    def query(self, sql, fmt="ArrowStream"):
+        """Execute a query and return the raw result."""
         if self._closed:
             raise err.InterfaceError("Connection closed")
 
         if isinstance(sql, str):
-            sql = sql.encode(self.encoding)
+            sql = sql.encode(self.encoding, "surrogateescape")
 
-        if isinstance(sql, bytearray):
-            sql = bytes(sql)
-
-        # drop last command return
-        if self._resp is not None:
-            self._resp = None
-
-        if DEBUG:
-            print("DEBUG: query:", sql)
         try:
-            res = self._session.query(sql, fmt="JSON")
-            if res.has_error():
-                raise err.DatabaseError(res.error_message())
-            self._resp = res.data()
+            result = self._conn.query(sql.decode(), fmt)
+            self._resp = result
+            return result
         except Exception as error:
-            raise err.InterfaceError("query err: %s" % error)
+            raise err.InterfaceError(f"Query error: {error}")
 
     def escape(self, obj, mapping=None):
-        """Escape whatever value you pass to it.
-
-        Non-standard, for internal use; do not use this in your applications.
-        """
-        if isinstance(obj, str):
-            return "'" + self.escape_string(obj) + "'"
-        if isinstance(obj, (bytes, bytearray)):
-            ret = self._quote_bytes(obj)
-            return ret
-        return converters.escape_item(obj, mapping=mapping)
+        """Escape whatever value you pass to it."""
+        return converters.escape_item(obj, mapping)
 
     def escape_string(self, s):
         return converters.escape_string(s)
 
     def _quote_bytes(self, s):
         return converters.escape_bytes(s)
 
-    def _read_query_result(self):
-        self._result = None
-        result = CHDBResult(self)
-        result.read()
-        self._result = result
-        return result.affected_rows
-
     def __enter__(self):
         """Context manager that returns a Cursor"""
         return self.cursor()
@@ -166,52 +92,9 @@ def __exit__(self, exc, value, traceback):
             self.rollback()
         else:
             self.commit()
+        self.close()
 
     @property
     def resp(self):
+        """Return the last query response"""
         return self._resp
-
-
-class CHDBResult(object):
-    def __init__(self, connection):
-        """
-        :type connection: Connection
-        """
-        self.connection = connection
-        self.affected_rows = 0
-        self.insert_id = None
-        self.warning_count = 0
-        self.message = None
-        self.field_count = 0
-        self.description = None
-        self.rows = None
-        self.has_next = None
-
-    def read(self):
-        # Handle empty responses (for instance from CREATE TABLE)
-        if self.connection.resp is None:
-            return
-
-        try:
-            data = json.loads(self.connection.resp)
-        except Exception as error:
-            raise err.InterfaceError("Unsupported response format:" % error)
-
-        try:
-            self.field_count = len(data["meta"])
-            description = []
-            for meta in data["meta"]:
-                fields = [meta["name"], meta["type"]]
-                description.append(tuple(fields))
-            self.description = tuple(description)
-
-            rows = []
-            for line in data["data"]:
-                row = []
-                for i in range(self.field_count):
-                    column_data = converters.convert_column_data(self.description[i][1], line[self.description[i][0]])
-                    row.append(column_data)
-                rows.append(tuple(row))
-            self.rows = tuple(rows)
-        except Exception as error:
-            raise err.InterfaceError("Read return data err:" % error)