| Bug #96588 | BIGINT column data truncated using prepared statements with C extension | ||
|---|---|---|---|
| Submitted: | 19 Aug 2019 17:12 | Modified: | 1 Mar 2022 18:59 |
| Reporter: | Will Miles | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | Connector / Python | Severity: | S2 (Serious) |
| Version: | 8.0.17 | OS: | Windows (Python 3.6) |
| Assigned to: | CPU Architecture: | Any | |
[20 Aug 2019 8:43]
MySQL Verification Team
Hello Will Miles, Thank you for the report. regards, Umesh
[1 Mar 2022 4:43]
Dan Ruley
This bug is still present as of 2/28/2022. If you select or insert a bigint type using prepared statements it will convert it to a normal int.
[1 Mar 2022 18:59]
Philip Olson
Posted by developer: Fixed as of the upcoming MySQL Connector/Python 8.0.29 release, and here's the proposed changelog entry from the documentation team: On Windows, and with the C extension with prepared=True, BIGINT data was seen as MYSQL_TYPE_LONG instead of MYSQL_TYPE_LONGLONG; this raised an overflow error with values over 2147483647. Thank you for the bug report. Related Bug: MySQL Bug #105254
Description: When SELECTing BIGINT columns, data appears to be retrieved using a buffer of MYSQL_TYPE_LONG instead of MYSQL_TYPE_LONGLONG. This causes data values to be truncated unexpectedly, as Python fully supports long integers. This problem does not apply to pure mode -- it is only relevant to the new feature of the C extension. How to repeat: import mysql.connector cnx = mysql.connector.connect(use_pure=False) cursor = cnx.cursor(prepared=True) cursor.execute("SELECT 922337203685477580") result = cursor.fetchall() print(result) Expected: [(922337203685477580,)] Returned: [(-858993460,)] Suggested fix: Use a 'long long' element in column_info.small_buffer for retrieving integral values instead of a 'long'. sizeof(long long) is usually smaller than sizeof(double) anyways, so it won't typically increase the buffer size.