Bug #77781 No alternative for max_long_data_size in 5.6

• Submitted: 19 Jul 2015 20:35
• Modified: 20 Jul 2015 18:47
• Reporter: Daniël van Eeden (OCA)
• Status: Verified
• Category: MySQL Server: Options
• Severity: S3 (Non-critical)
• Version: 5.6
• OS: Any
• CPU Architecture: Any

[19 Jul 2015 20:35] Daniël van Eeden

Description:
max_long_data_size was removed in 5.6 and replaced by max_allowed_packet.

However max_allowed_packet can be set to max 1G.

max_long_data_size could be raised to 4G.

Using mysql_stmt_send_long_data() to send chunks to send more than 1G doesn't work in 5.6 anymore.

Tested with 5.6.25.

How to repeat:
Use this:
https://github.com/dveeden/mysql_supersize/blob/master/C/supersize.c

With some notes on settings:
https://github.com/dveeden/mysql_supersize/blob/master/README.md

Suggested fix:
Add max_long_data_size and set to max_allowed_packet by default.

[20 Jul 2015 5:06] MySQL Verification Team

Hello Daniël,

Thank you for the report and test case.

Thanks,
Umesh

[20 Jul 2015 18:47] Daniël van Eeden

Note that in MariaDB 10.1 the server can write events which are larger than the max max_allowed_packet if max_long_data_size > max max_allowed_packet. This will break replication and point in time restore based on the binlogs.

So keep replication in mind when fixing this bug.