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From Maison Mo <momai...@yahoo.fr>
Subject Backup : snapshot at beginning or mixed content ?
Date Mon, 06 Sep 2010 16:32:41 GMT
Hello dear derby developers,

I have a question about database backup.

According to admin guide, there are two methods for that operation :
1 - freeze the DB with SYSCS_UTIL.SYSCS_FREEZE_DATABASE and perform a (hopefully quick) external
copy of database files ; then UNFREEZE

I wonder what happens when commits are performed during the backup.
- With method 1 I expect the commits to hang until the unfreeze
- With method 2 what happens exactly ? Does the commit go into the backup ? Always ? Never
? Does it depends on the table(s) on which the commit is performed ?

My problem is the following : I need to backup 2 differents databases, that are linked with
two different JEE applications. I can suspend these apps for a while, but not as long as the
time required to perform the backup (several minutes).
It would be nice if I could suspend the apps for one second, start the backups, then release
the apps and the backup would include only the commited record at the time the backup started.

Is that possible with derby ? If not, what kind of workaround could I use so that the databases
remain coherent in between them ?

Thank you in advance for your answers.

  M. Maison

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