Multiple ibdata nodes with same names, different paths maybe handled incorrectly

[Alexey Kopytov]

XtraBackup ignores the directory component in innodb_data_file_path and copies all ibdata nodes into the top-level backup directory. If the system InnoDB tablespace contains multiple nodes in different directories, and some nodes have identical names, it will attempt to copy different nodes with the same name into the same directory.

That will lead to an error for local backup, as XtraBackup will refuse to overwrite files. But with streaming backups the resulting stream will contain multiple "versions" of files that have the same name. Which will result in files being overwritten when extracting the stream.

For relative paths in innodb_data_file_path we could mimic the same directory layout in the backup directory/stream and thus avoid name conflicts. This will also require changes to --copy-back so it is able to identify multiple ibdata nodes in different subdirectories.

For absolute paths we could strip the leading / and convert them to paths relative to the top-level backup directory. I.e. /mnt/data1/ibdata1:1024M;/mnt/data2/ibdata1:1024M should yield the following files in backup directory (and innodb_data_file_path value in backup-my.cnf):

mnt/data1/ibdata1
mnt/data2/ibdata1

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXB-908