Hi,

The documentation is not very clear. I will change it, see below.

> 1) BACKUP SQL AND SCRIPT statement create an on-line backup ( while database 
> is running ) that is transactionally consistent that don't lock database 
> objects nor block other users.

The BACKUP and SCRIPT statement behave differently, this is already
documented. SCRIPT does lock the tables. BACKUP does not. However,
BACKUP still locks the database except when using the multi-threaded
mode (which is not fully tested however). So if you do want to backup
the database while other transactions are running, use the BACKUP
statement. And if you want to create a backup without blocking them,
then use BACKUP statement and the multi-threaded mode, but please note
this is not fully tested yet (the multi-threaded mode is not the
highest priority for me).

> 2) BACKUP TOOL can't be used to on-line backup ; even if file systems support 
> creating snapshots.

Right. The problem is that I have no idea what is the Java API to
actually create such a snapshot. If you know, please tell me.

Regards,
Thomas

----------------new backup documentation --------------------------

The BACKUP SQL statement and the Backup tool both create a zip file
with all database files. However, the contents of this file are not
human readable.

Unlike than the SCRIPT statement, the BACKUP statement does not lock
the database objects when using the multi-threaded mode, and therefore
does not block other users. The resulting backup is transactionally
consistent:

BACKUP TO 'backup.zip'

The Backup tool (org.h2.tools.Backup) can not be used to create a
online backup; the database must not be in use while running this
program.

Creating a backup by copying the database files while the database is
running is not supported, except if the file systems support creating
snapshots. The problem is that it can't be guaranteed that the data is
copied in the right order.

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