Re: Upgrade to 2.3.40 -> failed index

[Philip Guenther <guenther+ldapsoft@sendmail.com>]

On Mon, 4 Feb 2008, Howard Chu wrote:
> Paul B. Henson wrote:
...
> > I took another quick look at the BerkeleyDB documentation on the Oracle
> > site and did not see anything that seemed relevant to copying databases
> > between machines. Could I trouble you for a URL to see whether there is
> > anything in those procedures that might have been violated?
>
> http://www.oracle.com/technology/documentation/berkeley-db/db/ref/transapp/archival.html
>
> At a guess, you failed to copy the transaction log files to the slaves.

Or failed to perform catastrophic recovery instead of normal recovery. 
(I.e, db_recover must be invoked with the -c option.)


There's another catch: if the DB_LOG_AUTOREMOVE flag is in effect, then 
taking a hot backup may result in a broken backup if any transaction logs 
were removed during the backup.  If you don't know about this and check 
for it, you won't even know that the backup is bogus.

So, as a practical matter, if you're using DB_LOG_AUTOREMOVE, then you 
need to shut down before trying to back up the database at the DB level.

(To quote the DBENV->set_flags() manual:
    DB_LOG_AUTOREMOVE
	If set, Berkeley DB will automatically remove log files that
    are no longer needed. Automatic log file removal is likely to
    make catastrophic recovery impossible.

...and catastrophic recovery is necessary for hot backups.)


Philip Guenther