I enabled the lucene index cache for the mostly used properties and it made a huge difference!
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. 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
