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From istanbullu <yuksel.gu...@gmail.com>
Subject Re: Rollforward recovery problem
Date Thu, 06 Sep 2012 20:53:19 GMT

Hi Kathey,

Thanks for looking into this.

The sample DB I have is fairly large and contains confidential info, so I
cannot share it.  I will see if I can reproduce the problem with a simpler
scenario.  Also, I will try to reproduce it using ij.  What I currently have
are Java programs.  

In your example, did you see just one file under seg0?  Note that if I
delete all files under seg0, I do not see an issue: DB is restored
successfully.

Derby network server was not shutdown.  I tried to do rollforward recovery
over Network server.

Derby version is 10.5.3.0.

Thanks.

Yuksel


kmarsden wrote:
> 
> On 9/5/2012 1:44 PM, istanbullu wrote:
> <snip>
>> Now, here is the failing scenario:
>>
>> 1) I take a DB back-up by enabling log archive mode
>> 2) I delete a subset of files under seg0 directory of the original DB
>> (say
>> c5*.dat)
>> 3) Then, I run rollforward recovery script, and I DO NOT see the deleted
>> files restored from the backed-up DB created in step 1.  I run
>> consistency
>> check and it fails.
>>
>> Note that the only difference is that in successful scenario all files
>> under
>> seg0 are deleted.
>>
>> My scripts are along the lines of code snippets discussed in this
>> developerworks article:
>>
>> http://www.ibm.com/developerworks/data/library/techarticle/dm-0502thalamati/index.html
>>
>> Any comments appreciated.
>>
> 
> Thank you so much for thinking about backup and recovery and pointing to 
> the article.  I didn't know this article existed and will bookmark it 
> and promote it!
> 
> I have always instructed people restoring after corruption to make a zip 
> archive of the database  for analysis and then  remove a corrupt (or any 
> existing database) before restoring to that location.  I often see 
> corruptions that occur from restoring one database on top of another 
> (usually with operating system commands.)
> 
> I see now that the documentation says restore should delete the 
> existing  database :
> 
> http://db.apache.org/derby/docs/10.8/adminguide/tadminhubbkup44.html
> 
> so what you are describing sounds like a bug.
> 
> I tried reproducing on 10.8.2.2 - (1181258)  and trunk as follows: ( I 
> am using cygwin  so pardon the shell commands on windows)
> 
> I created the database:
> 
>   $java org.apache.derby.tools.ij
> ij version 10.8
> ij> connect 'jdbc:derby:wombat;create=true';
> ij> create table t (i int);
> 0 rows inserted/updated/deleted
> ij> create table t2 (i int);
> 0 rows inserted/updated/deleted
> ij> exit;
> 
> Found a file under seg0:
> $ls -l wombat/seg0/c470.dat
> -rwxrwxrwx 1 kmarsden None 8192 Sep  6 13:08 wombat/seg0/c470.dat
> 
> 
> $ Backed up with log archive mode
>   $java org.apache.derby.tools.ij
> ij version 10.8
> ij> connect 'jdbc:derby:wombat';
> ij>  CALL 
> SYSCS_UTIL.SYSCS_BACKUP_DATABASE_AND_ENABLE_LOG_ARCHIVE_MODE('c:/cygwin/tmp/backuplogarc/09_06_2012',1);
> 0 rows inserted/updated/deleted
> ij> exit;
> 
> Deleted the file:
> $rm wombat/seg0/c470.dat
> $ls -l wombat/seg0/c470.dat
> ls: cannot access wombat/seg0/c470.dat: No such file or directory
> 
> Restored with roll forward recovery:
> ij>connect 
> 'jdbc:derby:wombat;rollForwardRecoveryFrom=c:/cygwin/tmp/backuplogarc/09_06_2012/wombat';
> ij> exit;
> 
> My file was restored:
> 
>   $ls -l wombat/seg0/c470.dat
> rwxrwx 1 kmarsden None 8192 Sep  6 13:13 wombat/seg0/c470.dat
> 
> Can you provide a reproduction where the files don't get restored?
> 
> Also could you include the full Derby version from the derby.log? Was 
> Derby or network server fully shutdown before attempting the restore?
> 
> Thanks
> 
> Kathey
> 
> 

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