Implement the Connection.executemany() method

The executemany() method runs an SQL command for each sequence
of arguments in the given iterable.

Closes: #36

Author: elprans

asyncpg/connection.py

@@ -148,6 +148,27 @@ async def execute(self, query: str, *args, timeout: float=None) -> str:
                                                          True, timeout)
         return status.decode()
 
+    async def executemany(self, command: str, args, timeout: float=None):
+        """Execute an SQL *command* for each sequence of arguments in *args*.
+
+        Example:
+
+        .. code-block:: pycon
+
+            >>> await con.executemany('''
+            ...     INSERT INTO mytab (a) VALUES ($1, $2, $3);
+            ... ''')
+
+        :param command: Command to execute.
+        :args: An iterable containing sequences of arguments.
+        :param float timeout: Optional timeout value in seconds.
+        :return None: This method discards the results of the operations.
+
+        .. versionadded:: 0.7.0
+        """
+        stmt = await self._get_statement(command, timeout)
+        return await self._protocol.bind_execute_many(stmt, args, '', timeout)
+
     async def _get_statement(self, query, timeout):
         cache = self._stmt_cache_max_size > 0
 

asyncpg/protocol/coreproto.pxd

@@ -21,10 +21,11 @@ cdef enum ProtocolState:
     PROTOCOL_AUTH = 10
     PROTOCOL_PREPARE = 11
     PROTOCOL_BIND_EXECUTE = 12
-    PROTOCOL_CLOSE_STMT_PORTAL = 13
-    PROTOCOL_SIMPLE_QUERY = 14
-    PROTOCOL_EXECUTE = 15
-    PROTOCOL_BIND = 16
+    PROTOCOL_BIND_EXECUTE_MANY = 13
+    PROTOCOL_CLOSE_STMT_PORTAL = 14
+    PROTOCOL_SIMPLE_QUERY = 15
+    PROTOCOL_EXECUTE = 16
+    PROTOCOL_BIND = 17
 
 
 cdef enum AuthenticationMessage:
@@ -67,6 +68,12 @@ cdef class CoreProtocol:
     cdef:
         ReadBuffer buffer
         bint _skip_discard
+        bint _discard_data
+
+        # executemany support data
+        object _execute_iter
+        str _execute_portal_name
+        str _execute_stmt_name
 
         ConnectionStatus con_status
         ProtocolState state
@@ -95,6 +102,7 @@ cdef class CoreProtocol:
     cdef _process__auth(self, char mtype)
     cdef _process__prepare(self, char mtype)
     cdef _process__bind_execute(self, char mtype)
+    cdef _process__bind_execute_many(self, char mtype)
     cdef _process__close_stmt_portal(self, char mtype)
     cdef _process__simple_query(self, char mtype)
     cdef _process__bind(self, char mtype)
@@ -129,8 +137,12 @@ cdef class CoreProtocol:
 
     cdef _connect(self)
     cdef _prepare(self, str stmt_name, str query)
+    cdef _send_bind_message(self, str portal_name, str stmt_name,
+                            WriteBuffer bind_data, int32_t limit)
     cdef _bind_execute(self, str portal_name, str stmt_name,
                        WriteBuffer bind_data, int32_t limit)
+    cdef _bind_execute_many(self, str portal_name, str stmt_name,
+                            object bind_data)
     cdef _bind(self, str portal_name, str stmt_name,
                WriteBuffer bind_data)
     cdef _execute(self, str portal_name, int32_t limit)

asyncpg/protocol/coreproto.pyx

@@ -24,6 +24,11 @@ cdef class CoreProtocol:
 
         self._skip_discard = False
 
+        # executemany support data
+        self._execute_iter = None
+        self._execute_portal_name = None
+        self._execute_stmt_name = None
+
         self._reset_result()
 
     cdef _write(self, buf):
@@ -60,6 +65,9 @@ cdef class CoreProtocol:
                 elif state == PROTOCOL_BIND_EXECUTE:
                     self._process__bind_execute(mtype)
 
+                elif state == PROTOCOL_BIND_EXECUTE_MANY:
+                    self._process__bind_execute_many(mtype)
+
                 elif state == PROTOCOL_EXECUTE:
                     self._process__bind_execute(mtype)
 
@@ -194,6 +202,49 @@ cdef class CoreProtocol:
             # EmptyQueryResponse
             self.buffer.consume_message()
 
+    cdef _process__bind_execute_many(self, char mtype):
+        cdef WriteBuffer buf
+
+        if mtype == b'D':
+            # DataRow
+            self._parse_data_msgs()
+
+        elif mtype == b's':
+            # PortalSuspended
+            self.buffer.consume_message()
+
+        elif mtype == b'C':
+            # CommandComplete
+            self._parse_msg_command_complete()
+
+        elif mtype == b'E':
+            # ErrorResponse
+            self._parse_msg_error_response(True)
+
+        elif mtype == b'2':
+            # BindComplete
+            self.buffer.consume_message()
+
+        elif mtype == b'Z':
+            # ReadyForQuery
+            self._parse_msg_ready_for_query()
+            if self.result_type == RESULT_FAILED:
+                self._push_result()
+            else:
+                try:
+                    buf = <WriteBuffer>next(self._execute_iter)
+                except StopIteration:
+                    self._push_result()
+                else:
+                    # Next iteration over the executemany() arg sequence
+                    self._send_bind_message(
+                        self._execute_portal_name, self._execute_stmt_name,
+                        buf, 0)
+
+        elif mtype == b'I':
+            # EmptyQueryResponse
+            self.buffer.consume_message()
+
     cdef _process__bind(self, char mtype):
         if mtype == b'E':
             # ErrorResponse
@@ -275,6 +326,14 @@ cdef class CoreProtocol:
                 raise RuntimeError(
                     '_parse_data_msgs: first message is not "D"')
 
+        if self._discard_data:
+            while True:
+                buf.consume_message()
+                if not buf.has_message() or buf.get_message_type() != b'D':
+                    self._skip_discard = True
+                    return
+
+        if ASYNCPG_DEBUG:
             if type(self.result) is not list:
                 raise RuntimeError(
                     '_parse_data_msgs: result is not a list, but {!r}'.
@@ -424,6 +483,7 @@ cdef class CoreProtocol:
         self.result_row_desc = None
         self.result_status_msg = None
         self.result_execute_completed = False
+        self._discard_data = False
 
     cdef _set_state(self, ProtocolState new_state):
         if new_state == PROTOCOL_IDLE:
@@ -537,16 +597,11 @@ cdef class CoreProtocol:
 
         self.transport.write(memoryview(packet))
 
-    cdef _bind_execute(self, str portal_name, str stmt_name,
-                       WriteBuffer bind_data, int32_t limit):
+    cdef _send_bind_message(self, str portal_name, str stmt_name,
+                            WriteBuffer bind_data, int32_t limit):
 
         cdef WriteBuffer buf
 
-        self._ensure_connected()
-        self._set_state(PROTOCOL_BIND_EXECUTE)
-
-        self.result = []
-
         buf = self._build_bind_message(portal_name, stmt_name, bind_data)
         self._write(buf)
 
@@ -558,6 +613,39 @@ cdef class CoreProtocol:
 
         self._write_sync_message()
 
+    cdef _bind_execute(self, str portal_name, str stmt_name,
+                       WriteBuffer bind_data, int32_t limit):
+
+        cdef WriteBuffer buf
+
+        self._ensure_connected()
+        self._set_state(PROTOCOL_BIND_EXECUTE)
+
+        self.result = []
+
+        self._send_bind_message(portal_name, stmt_name, bind_data, limit)
+
+    cdef _bind_execute_many(self, str portal_name, str stmt_name,
+                            object bind_data):
+
+        cdef WriteBuffer buf
+
+        self._ensure_connected()
+        self._set_state(PROTOCOL_BIND_EXECUTE_MANY)
+
+        self.result = None
+        self._discard_data = True
+        self._execute_iter = bind_data
+        self._execute_portal_name = portal_name
+        self._execute_stmt_name = stmt_name
+
+        try:
+            buf = <WriteBuffer>next(bind_data)
+        except StopIteration:
+            self._push_result()
+        else:
+            self._send_bind_message(portal_name, stmt_name, buf, 0)
+
     cdef _execute(self, str portal_name, int32_t limit):
         cdef WriteBuffer buf
 

asyncpg/protocol/protocol.pyx

@@ -162,6 +162,37 @@ cdef class BaseProtocol(CoreProtocol):
 
         return await self._new_waiter(timeout)
 
+    async def bind_execute_many(self, PreparedStatementState state, args,
+                                str portal_name, timeout):
+
+        if self.cancel_waiter is not None:
+            await self.cancel_waiter
+        if self.cancel_sent_waiter is not None:
+            await self.cancel_sent_waiter
+            self.cancel_sent_waiter = None
+
+        self._ensure_clear_state()
+
+        # Make sure the argument sequence is encoded lazily with
+        # this generator expression to keep the memory pressure under
+        # control.
+        data_gen = (state._encode_bind_msg(b) for b in args)
+        arg_bufs = iter(data_gen)
+
+        waiter = self._new_waiter(timeout)
+
+        self._bind_execute_many(
+            portal_name,
+            state.name,
+            arg_bufs)
+
+        self.last_query = state.query
+        self.statement = state
+        self.return_extra = False
+        self.queries_count += 1
+
+        return await waiter
+
     async def bind(self, PreparedStatementState state, args,
                    str portal_name, timeout):
 
@@ -405,6 +436,9 @@ cdef class BaseProtocol(CoreProtocol):
             elif self.state == PROTOCOL_BIND_EXECUTE:
                 self._on_result__bind_and_exec(waiter)
 
+            elif self.state == PROTOCOL_BIND_EXECUTE_MANY:
+                self._on_result__bind_and_exec(waiter)
+
             elif self.state == PROTOCOL_EXECUTE:
                 self._on_result__bind_and_exec(waiter)
 

tests/test_execute.py

@@ -97,3 +97,16 @@ async def test_execute_script_interrupted_terminate(self):
             await fut
 
         self.con.terminate()
+
+    async def test_execute_many_1(self):
+        result = await self.con.executemany('''
+            SELECT $1::text, $2::int
+        ''', (['a', 1], ['b', 2], ['c', 3], ['d', 4]))
+
+        self.assertIsNone(result)
+
+        result = await self.con.executemany('''
+            SELECT $1::text, $2::int
+        ''', tuple())
+
+        self.assertIsNone(result)