[Tm4j-developers] RE: [TM4J-users] slow tm export

[Kal A. <ka...@te...>]

Hi Conal,

I'm going to have to take a look at this in more detail - it may be that
it will be possible to create a lower-level exporter specifically for
the Hibernate backend that doesn't have this performance problem.

In the meantime, I can only suggest that you take a look through
Hibernate's documentation and that of your database to see if there are
any runtime configuration options that might help improve performance.

Cheers,

Kal

On Sun, 2004-09-12 at 23:54, Conal Tuohy wrote:
> Thanks Kal!
> 
> I opened a transaction before walking my topic map, but sadly it hasn't speeded it up at all :-(
> 
> Here's the code I used:
> 
> 	/* get the topic map from the topic map manager */
> 	var TopicMapManager = cocoon.getComponent("org.tm4j.tm4web.cocoon.TopicMapManagerComponent");
> 	var map = TopicMapManager.getTopicMap("nzetc");
> 	cocoon.releaseComponent(TopicMapManager);
> 
> 	/* write the topic map to a file */
> 	var walker = new Packages.org.tm4j.topicmap.utils.TopicMapWalker();
> 	var writer = new Packages.org.tm4j.topicmap.utils.XTMWriter();
> 	var file = new java.io.File(export_filename);
> 	var os = new java.io.FileOutputStream(file);
> 	var of = new Packages.org.apache.xml.serialize.OutputFormat();
> 	of.setEncoding("UTF-8");
> 	of.setIndenting(true);
> 	of.setIndent(2);
> 	var serializer = new Packages.org.apache.xml.serialize.XMLSerializer(os, of);
> 	walker.setHandler(writer);
> 	writer.setContentHandler(serializer);
> 	
> 	var txn = map.getProvider().openTransaction();
> 	try {
> 	  walker.walk(map);
> 	} finally {
> 	  txn.abort();
> 	}
> 	
> 	/* walker.walk(map); */
> 	cocoon.sendPage("export/nzetc.xtm");
> 
> Cheers
> 
> Con
> 
> > My guess is that the walk is just doing to many transactions. If you
> > don't have an "outer" transaction wrapping that walk, then 
> > each call to
> > the API will result in a separate transaction against the database -
> > which amounts to quite a lot of transactions to walk the whole map.
> > 
> > What I would recommend you try is creating a transaction to 
> > wrap around
> > the walk. If a transaction is already in progress, then the TM4J
> > Hibernate code will use that txn instead of creating one.
> > 
> > The code would be something like this:
> > 
> > ProviderTransaction txn = provider.getTransaction();
> > try {
> >   walker.walk();
> > } finally {
> >   txn.abort();
> > }
> 
> 
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-- 
Kal Ahmed <ka...@te...>
techquila