MySQL Bugs: #37249: Incomplete error message during Restore for full disk

Bug #37249	Incomplete error message during Restore for full disk
Submitted:	6 Jun 2008 16:18	Modified:	20 Dec 2013 8:27
Reporter:	Hema Sridharan	Email Updates:
Status:	Won't fix	Impact on me:	None
Category:	MySQL Server: Backup	Severity:	S3 (Non-critical)
Version:	mysql-6.0-backup-myisam	OS:	Linux
Assigned to:	Assigned Account	CPU Architecture:	Any

Description:
1) I create huge database (few tables and data in them).
2) I backup database to a location where there is less space (almost
full disk). Half the way during Backup, I get invalid error message,
ERROR 1648 (HY000): Error when writing data from MyISAM backup driver
(data block for table #2)

The above error number shows different message in the Reference manuals.
This will cause confusion to the user. Error messages needs to be
properly documented.
3) I drop database and perform Restore.
4) I get an incomplete error message during Restore.
ERROR 1697 (HY000): ckup image

How to repeat:
mysql> backup database db2 to '/data1/backup_dmp/online_ba';
ERROR 1648 (HY000): Error when writing data from MyISAM backup driver
(data block for table #2)

mysql> restore from '/data1/backup_dmp/onlineba';
ERROR 1697 (HY000): ckup image

The error message when disk goes full, seems to be dependent on the driver that experience the problem. With current head of mysql-6.0-backup branch, I gett the following ouput:

MyIsam Native Driver:
ERROR 1650 (HY000): Error when writing data from MyISAM backup driver (data block for table #1)

Consistent Snapshot Driver:
ERROR 1736 (HY000): Backup/Restore: Error on close of backup stream

When trying to restore an image from a backup that experienced disk full disk issue, the error message I get is:
ERROR 1699 (HY000): Error when reading summary section of backup image

In order to test backup with full disk without having to fill a disk, I created a loop device as follows:

dd if=/dev/zero of=/home/oysteing/file bs=1k count=100  #100kB file
sudo losetup /dev/loop0 /home/oysteing/file
sudo mkfs -t ext2 /dev/loop0 100
cd /home/oysteing/mysql/mysql-6.0-backup-37249/mysql-test/var/master-data
mkdir backupfs
sudo mount -t ext2 /dev/loop0 backupfs
sudo chmod 777 backupfs

To use this small file system for backup, I do 
backup database test to 'backupfs/b.bak'

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/100437

3096 Thava Alagu	2010-02-16
      Bug#37249 Incomplete error message during Restore for full disk
      
      When the disk is full, backup/restore operation fails
      with cryptic error messages.
      
      This fix introduces a mechanism to propagate the error
      code from OS level (mysys errno) to backup layer.
      In some cases, the errno is also printed along with
      error message which often helps to track the precise
      error conditions which caused the failure.
      Some messages improved to exactly point to file
      writing problem with associated error number.

Patch not approved - see review.

The 6.x project has been abandoned.