BUG21530841: Select statement fails for results with more than 4096 columns

nmariz · nmariz · commit 2d1a626b798f · 2016-12-02T11:14:54.000Z
Using SELECT statements having results with more than 4096 columns fails.
MySQL has hard limit of 4096 columns per table, but when using table joins
this number can increase.

This patch fixes this issue by removing the test for maximum table columns.

A test was added for regression.
diff --git a/lib/mysql/connector/protocol.py b/lib/mysql/connector/protocol.py
@@ -227,8 +227,6 @@ def parse_column_count(self, packet):
         """Parse a MySQL packet with the number of columns in result set"""
         try:
             count = utils.read_lc_int(packet[4:])[1]
-            if count > MAX_MYSQL_TABLE_COLUMNS:
-                return None
             return count
         except (struct.error, ValueError):
             raise errors.InterfaceError("Failed parsing column count")
diff --git a/tests/test_bugs.py b/tests/test_bugs.py
@@ -4163,3 +4163,36 @@ def test_unicode_password(self):
             self.fail('Failed using password with unicode characters')
         else:
             cnx.close()
+
+
+class BugOra21530841(tests.MySQLConnectorTests):
+    """BUG#21530841: SELECT FAILS WITH ILLEGAL RESULT SET ERROR WHEN COLUMN
+    COUNT IN RESULT > 4096
+    """
+    def setUp(self):
+        config = tests.get_mysql_config()
+        self.cnx = connection.MySQLConnection(**config)
+        self.tbl = "Bug21530841"
+        self.cnx.cmd_query("DROP TABLE IF EXISTS {0}".format(self.tbl))
+
+    def tearDown(self):
+        self.cnx.cmd_query("DROP TABLE IF EXISTS {0}".format(self.tbl))
+        self.cnx.close()
+
+    def test_big_column_count(self):
+        cur = self.cnx.cursor(raw=False, buffered=False)
+        # Create table with 512 Columns
+        table = "CREATE TABLE t ({0})".format(
+            ", ".join(["c{0} INT".format(idx) for idx in range(512)]))
+        cur.execute(table)
+
+        # Insert 1 record
+        cur.execute("INSERT INTO t(c1) values (1) ")
+        self.cnx.commit()
+
+        # Select from 10 tables
+        query = "SELECT * FROM {0} WHERE a1.c1 > 0".format(
+            ", ".join(["t a{0}".format(idx) for idx in range(10)]))
+        cur.execute(query)
+        cur.fetchone()
+        cur.close()
