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From "Stefan Guggisberg" <stefan.guggisb...@gmail.com>
Subject Re: ObjectPersistenceManager vs SimpleDbPersistenceManager
Date Wed, 08 Aug 2007 15:53:20 GMT
hi phillip

On 8/7/07, Phillip Rhodes <spamsucks@rhoderunner.com> wrote:
> Hello everyone,
>
> I did some debugging for my performance problems with SimpleDbPersistenceManager.
> I ran SimpleDbPersistenceManager with jdbclogger and found that Jackrabbit will issue
2+ sql queries for each node as I iterator through the NodeIterator.  This does not scale
well for me.

please note that items read from the persistence layer are cached.
those items will be delivered from cache on subsequent reads
(unless they've been evicted in the mean time of course).

>
> I am considering switching my workspace to use the ObjectPersistenceManager .  I understand
it is not reliable as the SimpleDbPersistenceManager, but since I won't be issuing 400+ database
queries, I hope the performance for my application will improve.

what db are you using? i doubt that you'll see a dramatic performance
improvement
when compared to using embedded derby. furthermore, derby supports transactions.

>
> Am I risking the entire repository becoming corrupt, or just a few nodes becoming corrupt?
 I don't mind a few nodes becoming corrupt, but if the entire repo can become corrupt if the
repository is killed, I would appreciate knowing this!

well, if e.g. the root node or something like /myapp:products gets
corrupt you're in trouble.
it's like a dos file system, when your FAT gets corrupt you may end up
with a pretty mess.

personally i wouldn't recommend using the file system-based pm's,
certainly not for production systems.

cheers
stefan

>
>
>
>
> Thank you as always.
> Phillip
>
>
>

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