See below for more informations (Traceback, version)

Summary

I'm encountering a weird and hard-to-reproduce bug using execute_many() from the official MariaDB Python connector. Under very specific conditions, the method raises a mariadb.InterfaceError with no clear explanation.

The issue is data-sensitive: only certain inputs trigger it. No SQL or data syntax error is reported — just a crash deep in the driver's internal _execute_bulk() method.

Minimal reproducible example

This is the exact query and data shape I'm sending:

query = "UPDATE point SET building_density = ? WHERE id_point = ?"

updates = [(0.25555, i) for i in range(225051, 225631)]

cursor.executemany(query, updates)  # Crashes here with InterfaceError

However, very similar calls do not crash:

[(0, i) for i in range(225051, 225631)]        # Works

[(0.25555, i) for i in range(225051, 225632)]  # Works

[(0.25555, i) for i in range(225052, 225632)]  # Works

Workaround found

If I split the updates into smaller chunks, the error disappears completely:

for chunk in [updates[i:i+100] for i in range(0, len(updates), 100)]:

    cursor.executemany(query, chunk)  # All chunks run fine

Also, using .execute() in a loop works perfectly on the same data.
The bug does not depend on the total byte size (~14 KB), nor on the number of rows (580).

Changing float precision, ID ranges, or order of updates doesn't help — it appears to be an edge case of executemany()'s bulk handling.

I have tried installing different versions of the MariaDB connector (from 1.1.7 to 1.1.12), but the issue persists.

What I need

Confirmation that this is a bug in the MariaDB driver.

Possibly a fix or a way to disable BULK_OPERATIONS and fallback to safe mode.

Or a documented explanation of what conditions can break executemany() like this.

Thanks in advance!

Traceback

Traceback (most recent call last):
File "/myfolder/database.py", line 43, in execute_many
self.cursor.executemany(query, params_list)
File "/usr/local/lib/python3.12/site-packages/mariadb/cursors.py", line 359, in executemany
self._execute_bulk()
mariadb.InterfaceError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/myfolder/database.py", line 50, in execute_many
self.conn.rollback()
File "/usr/local/lib/python3.12/site-packages/mariadb/connections.py", line 192, in rollback
self._read_response()
mariadb.InterfaceError

Versions

Database table schema:

id_point INT(11) PRIMARY KEY AUTO_INCREMENT,

building_density FLOAT