Bug #34181 Backup: crash if @@max_heap_table_size is small

• Submitted: 31 Jan 2008 0:19
• Modified: 8 Oct 2009 12:01
• Reporter: Peter Gulutzan
• Status: Can't repeat
• Category: MySQL Server: Backup
• Severity: S3 (Non-critical)
• Version: 6.0.5-alpha-debug
• OS: Linux (SUSE 10 64-bit)
• Assigned to: Sanjay Manwani
• CPU Architecture: Any

[31 Jan 2008 0:19] Peter Gulutzan

Description:
I'm using mysql-6.0-backup.

I create a database.
I create an empty table.
I set @@max_heap_table_size = 2000.
I try to backup the database.

Crash.

How to repeat:
mysql> create database k;
Query OK, 1 row affected (0.00 sec)

mysql> use k
Database changed
mysql> set @@max_heap_table_size = 2000;
Query OK, 0 rows affected (0.00 sec)

mysql> create table t (s1 int) engine=memory;
Query OK, 0 rows affected (0.00 sec)

mysql> backup database k to '74';
ERROR 2013 (HY000): Lost connection to MySQL server during query

[31 Jan 2008 0:38] MySQL Verification Team

Thank you for the bug report. Verified as describde.

Database changed
mysql> set @@max_heap_table_size = 2000;
Query OK, 0 rows affected (0.00 sec)

mysql> create table t (s1 int) engine=memory;
Query OK, 0 rows affected (0.01 sec)

mysql> backup database k to '74';
ERROR 2013 (HY000): Lost connection to MySQL server during query
mysql>

[8 Oct 2009 12:01] Sanjay Manwani

It seems this is an old bug, the heap size limit is checked against a minimum of 16484 and reset to this limit if it is less with a warning:
Warnings:
Warning 1292    Truncated incorrect max_heap_table_size value: '2000'