Performance optiomizations:

- Result sets
Convert named_tuple and dictinuary result sets directly from netbuffer,
instead to fetch them in tuples and convert it afterwards

- fetch rows()
Use MrdbCursor_fetchrows() c function for fetchmany/fetchall.

mariadb/cursors.py

@@ -18,7 +18,6 @@
 #
 
 import mariadb
-import collections
 import datetime
 from numbers import Number
 from mariadb.constants import CURSOR, STATUS, CAPABILITY, INDICATOR
@@ -28,6 +27,8 @@ PARAMSTYLE_QMARK = 1
 PARAMSTYLE_FORMAT = 2
 PARAMSTYLE_PYFORMAT = 3
 
+ROWS_ALL = -1
+
 RESULT_TUPLE = 0
 RESULT_NAMEDTUPLE = 1
 RESULT_DICTIONARY = 2
@@ -410,17 +411,7 @@ class Cursor(mariadb._mariadb.cursor):
         self.check_closed()
 
         row = self._fetch_row()
-        if not row:
-            return row
-        if self._resulttype == RESULT_DICTIONARY:
-            ret = dict(zip(list(d[0] for d in self.description), row))
-        elif self._resulttype == RESULT_NAMEDTUPLE:
-            ret = collections.namedtuple('Row1', list(d[0]
-                                         for d in self.description))
-            ret = ret._make(row)
-        else:
-            ret = row
-        return ret
+        return row
 
     def fetchmany(self, size: int = 0):
         """
@@ -440,13 +431,9 @@ class Cursor(mariadb._mariadb.cursor):
         """
         self.check_closed()
 
-        rows = []
         if size == 0:
             size = self.arraysize
-        for count in range(0, size):
-            row = self.fetchone()
-            if row:
-                rows.append(row)
+        rows = super().fetchrows(size)
         return rows
 
     def fetchall(self):
@@ -458,7 +445,7 @@ class Cursor(mariadb._mariadb.cursor):
         produce a result set or execute() wasn't called before.
         """
         self.check_closed()
-        rows = super().fetchall()
+        rows = super().fetchrows(ROWS_ALL)
 
         if self._connection._converter:
             for idx, row in enumerate(rows):
@@ -474,19 +461,7 @@ class Cursor(mariadb._mariadb.cursor):
                         tmp_l[i] = v
                 rows[idx] = tuple(tmp_l)
 
-        if self._resulttype == RESULT_TUPLE:
-            return rows
-
-        ret = []
-        for row in rows:
-            if self._resulttype == RESULT_DICTIONARY:
-                new_row = dict(zip(list(d[0] for d in self.description), row))
-            elif self._resulttype == RESULT_NAMEDTUPLE:
-                new_row = collections.namedtuple('Row1', list(d[0]
-                                                 for d in self.description))
-                new_row = new_row._make(row)
-            ret.append(new_row)
-        return ret
+        return rows
 
     def __iter__(self):
         return iter(self.fetchone, None)

mariadb/mariadb_cursor.c

@@ -40,7 +40,7 @@ static PyObject *
 MrdbCursor_execute_text(MrdbCursor *self, PyObject *args);
 
 static PyObject *
-MrdbCursor_fetchall(MrdbCursor *self);
+MrdbCursor_fetchrows(MrdbCursor *self, PyObject *args);
 
 static PyObject *
 MrdbCursor_parse(MrdbCursor *self, PyObject *args);
@@ -128,8 +128,8 @@ static PyMethodDef MrdbCursor_Methods[] =
     {"fetchone", (PyCFunction)MrdbCursor_fetchone,
         METH_NOARGS,
         cursor_fetchone__doc__,},
-    {"fetchall", (PyCFunction)MrdbCursor_fetchall,
-        METH_NOARGS,
+    {"fetchrows", (PyCFunction)MrdbCursor_fetchrows,
+        METH_VARARGS,
         NULL},
     {"_nextset", (PyCFunction)MrdbCursor_nextset,
         METH_NOARGS,
@@ -193,6 +193,11 @@ static struct PyMemberDef MrdbCursor_Members[] =
         offsetof(MrdbCursor, parseinfo.command),
         0,
         MISSING_DOC},
+    {"_resulttype",
+        T_UINT,
+        offsetof(MrdbCursor, result_format),
+        0,
+        MISSING_DOC},
     {"_text",
         T_BOOL,
         offsetof(MrdbCursor, parseinfo.is_text),
@@ -1212,10 +1217,17 @@ error:
 }
 
 static PyObject *
-MrdbCursor_fetchall(MrdbCursor *self)
+MrdbCursor_fetchrows(MrdbCursor *self, PyObject *args)
 {
     PyObject *List;
     unsigned int field_count= self->field_count;
+    uint64_t row_count;
+
+    if (!PyArg_ParseTuple(args, "K", &row_count))
+    {
+        return NULL;
+    }
+
 
     MARIADB_CHECK_STMT(self);
 
@@ -1231,7 +1243,7 @@ MrdbCursor_fetchall(MrdbCursor *self)
         return NULL;
     }
 
-    while (!MrdbCursor_fetchinternal(self))
+    for (uint64_t i=0; i < row_count && !MrdbCursor_fetchinternal(self); i++)
     {
         uint32_t j;
         PyObject *Row;