db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: [jira] Commented: (DERBY-239) Need a online backup feature that does not block update operations when online backup is in progress.
Date Sat, 29 Oct 2005 17:43:29 GMT
I like option 1, make sure it is well documented.  I actually lean
toward even stronger, have the command commit the current transaction
before and after the backup.

Suresh Thalamati (JIRA) wrote:
>     [ http://issues.apache.org/jira/browse/DERBY-239?page=comments#action_12356240 ]

> Suresh Thalamati commented on DERBY-239:
> ----------------------------------------
> What to do if backup is started in a transaction that  already has unlogged operations
> In  previous discussions about online backup, it was concluded that existing 
> backup procedures calls will WAIT for the transaction with unlogged 
> operations to commit before proceeding with the backup. One issue that was
> missing from the discussion was, what to do if user starts a backup 
> in the same transaction that has unlogged operations executed before the backup call.

> WAIT will  not be an acceptable option here, because backup call will wait forever. 
> I can think of two ways this issue can be addressed:
> 1) Add a restriction that backup procedures can only be called in a brand
>    NEW transaction. And also implicitly commit the backup transaction at the end of the

>    backup. Commit is not required as such to solve this problem, but it would
>    be cleaner because backup itself is not a rollback-able operation. 
> 2) Make backup procedures fail, if transaction that it is started in 
>    contains unlogged operations.
> I am inclined towards implementing the first option. Any comments/suggestion 
> will be appreciated. 
> Thanks
> -suresht
>>Need a online backup feature  that does not block update operations   when online
backup is in progress.
>>         Key: DERBY-239
>>         URL: http://issues.apache.org/jira/browse/DERBY-239
>>     Project: Derby
>>        Type: New Feature
>>  Components: Store
>>    Versions:
>>    Reporter: Suresh Thalamati
>>    Assignee: Suresh Thalamati
>> Attachments: onlinebackup.html, onlinebackup_1.diff
>>Currently Derby allows users to perfoms  online backups using SYSCS_UTIL.SYSCS_BACKUP_DATABASE()
procedure,  but while the backup is in progress, update operations are temporarily blocked,
but read operations can still proceed.
>>Blocking update operations can be real issue specifically in client server environments,
because user requests will be blocked for a long time if a 
>>backup is in the progress on the server.

View raw message