2010/5/17 Kiss Miklós <kissmik...@freemail.hu> > I enabled the lucene index cache for the mostly used properties and it > made a huge difference! > Great
> > Regarding the VM heap size, I started with 128MB but already tried to > increase it to 512MB but didn't help. Now I'm trying to estimate the > actual memory requirement. I guess that using lucene index cache further > increases the memory requirement. > Yeah it does... do you have much RAM in your machine? try to increase the heap to 1 or 2 Gb and see what happens. > > Miklós > > 2010.05.17. 11:15 keltezéssel, Mattias Persson írta: > > 2010/5/17 Kiss Miklós<kissmik...@freemail.hu> > > > > > >> Hello, > >> > >> Thanks for the answer. > >> No I haven't looked at lucene index cache yet but will soon, thanks for > >> the tip. > >> The strings I store are mostly about 10 characters long but I also have > >> some about 30 chars. I wouldn't consider these as 'big strings'. > >> > >> > > That's a very common (and rather optimal for Neo4j) string size. > > > > Is it a good choice to put all write operations into one transaction? > > > >> This means in my case a few thousand nodes (2-5000) and about 4-5 times > >> more relation. Or would it give better performance if I sliced operation > >> into smaller transactions? What would be the optimal transaction size? > >> > >> > > That should yield a good write performance, yes. How much heap have you > > given the JVM? Write operations in a transaction is kept in memory until > > committed so if you don't have a big heap size it can be a problem and > cause > > out-of-memory problems like you encountered... > > > > > > > >> Thanks, > >> Miklos > >> > >> 2010.05.17. 9:35 keltezéssel, Mattias Persson írta: > >> > >>> Hi, sorry for a late response. > >>> > >>> Yep, this seems like an excellent fit for Neo4j. Regarding lucene index > >>> lookup performance: have you looked at enabling caching > >>> http://wiki.neo4j.org/content/Indexing_with_IndexService#Caching ? It > >>> > >> can > >> > >>> speed up lookups considerably. > >>> > >>> Do you store very big strings or just few words? Neo4j currently isn't > >>> optimal at storing big strings. For this an integration with another > >>> database could be a solution. > >>> > >>> 2010/5/10 Kiss Miklós<kissmik...@freemail.hu> > >>> > >>> > >>> > >>>> Hello, > >>>> > >>>> I'd like to ask if using Neo4j would be a good solution for the > >>>> following scenario. > >>>> I have an application which performs some natural language text > >>>> analysis. I want to put the results of this analysis into a database. > I > >>>> have words, stems, collocations, themes and many relations between > them. > >>>> This is why neo4j seems to be a good solution. > >>>> However, I ran into performance problems: I need to use lucene index > >>>> service heavily (I have to look up if a node I'm up to store already > >>>> exists) which I think is a bit slow. The other problem is java heap > >>>> space: some documents cause my app to halt with out of memory > exception > >>>> (for which I couldn't yet find the reason). > >>>> > >>>> My questions are: > >>>> 1, Is my data storage scenario a good one (nodes = words, relations = > >>>> relations) or there could be a better one? > >>>> 2, How should I perform the lookup of nodes in the database? > >>>> 3, Or should I use some other database? > >>>> > >>>> Thanks in advance, > >>>> Miklós > >>>> _______________________________________________ > >>>> Neo mailing list > >>>> User@lists.neo4j.org > >>>> https://lists.neo4j.org/mailman/listinfo/user > >>>> > >>>> > >>>> > >>> > >>> > >>> > >> _______________________________________________ > >> Neo mailing list > >> User@lists.neo4j.org > >> https://lists.neo4j.org/mailman/listinfo/user > >> > >> > > > > > > > > _______________________________________________ > Neo mailing list > User@lists.neo4j.org > https://lists.neo4j.org/mailman/listinfo/user > -- Mattias Persson, [matt...@neotechnology.com] Hacker, Neo Technology www.neotechnology.com _______________________________________________ Neo mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
