Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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1.0.11
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None
Description
the following test runs an INSERT..RETURNING that retrieves a value from a related "sequence" table. on mariadb-connector, it crashes with mariadb.InterfaceError: Lost connection to MySQL server during query. The same tests succeeds with most other major MySQL drivers, mysqlclient, pymysql (this is for SQLAlchemy). The test case below runs first on mysqlclient as a demo and then on mariadb-connector where it crashes.
import mariadb
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import MySQLdb
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def run_test(conn, p):
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cursor = conn.cursor()
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cursor.execute("DROP TABLE IF EXISTS t2")
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cursor.execute("DROP TABLE IF EXISTS t1")
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cursor.execute(
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"""
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CREATE TABLE t2 (
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nextid INTEGER
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)ENGINE=MyISAM
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"""
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)
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cursor.execute(
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"""
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CREATE TABLE t1 (
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id INTEGER NOT NULL,
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data VARCHAR(30),
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PRIMARY KEY (id)
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)ENGINE=MyISAM
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"""
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)
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cursor.execute(f"""INSERT INTO t2 (nextid) VALUES ({p})""", (1,))
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cursor.execute(
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f"""
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INSERT INTO t1 (id, data) VALUES
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((SELECT max(t2.nextid) AS max_1 FROM t2), {p}) RETURNING t1.id""",
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("hi",),
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)
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rows = cursor.fetchall()
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cursor.close()
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conn.close()
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print(f"Connection {conn} succeeded")
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mysqldb_conn = MySQLdb.connect(
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user="scott", password="tiger", host="localhost", db="test"
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)
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mariadb_conn = mariadb.connect(
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user="scott", password="tiger", host="localhost", db="test"
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)
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run_test(mysqldb_conn, "%s")
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run_test(mariadb_conn, "?")
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output:
Connection <_mysql.connection closed at 0xc00b40> succeeded
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Traceback (most recent call last):
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File "/home/classic/dev/sqlalchemy/test3.py", line 54, in <module>
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run_test(mariadb_conn, "?")
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File "/home/classic/dev/sqlalchemy/test3.py", line 31, in run_test
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cursor.execute(
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mariadb.InterfaceError: Lost connection to MySQL server during query
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Attachments
Issue Links
- causes
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- Closed
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Activity
Thanks zzzeek, put MDEV-28740 as the server crashing bug, but leaving this open in case there's something incorrect in the python implementation.
Server crashes only with 1.0 branch, not with 1.1. The difference between these branches is, that 1.0 uses binary protocol, while 1.1 uses text protocol (since there are no parameters to substitute).
ah I didnt realize the server is actually where the bug is, great thanks for looking into it.
seems to be any subquery, not just with a separate table , it needs to have parameters present
import mariadbimport MySQLdbdef run_test(conn, p):cursor = conn.cursor()cursor.execute("DROP TABLE IF EXISTS t1")cursor.execute("""CREATE TABLE t1 (id INTEGER NOT NULL,data VARCHAR(30),PRIMARY KEY (id))ENGINE=MyISAM""")cursor.execute(f"""INSERT INTO t1 (id, data) VALUES((SELECT CAST(1 AS SIGNED INTEGER) AS anon_1), {p}) RETURNING t1.id""",("hi",),)rows = cursor.fetchall()cursor.close()conn.close()print(f"Connection {conn} succeeded")mysqldb_conn = MySQLdb.connect(user="scott", password="tiger", host="localhost", db="test")mariadb_conn = mariadb.connect(user="scott", password="tiger", host="localhost", db="test")run_test(mysqldb_conn, "%s")run_test(mariadb_conn, "?")same result