It could also be that you are running up against Lucene index size limitations. In that case, 3.0 will help you when it is released.
-- Chris Vest System Engineer, Neo Technology [ skype: mr.chrisvest, twitter: chvest ] > On 04 Apr 2016, at 21:15, Chris Vest <[email protected]> wrote: > > Lucene does not use the Neo4j page cache, so try setting > dbms.pagecache.memory to a lower value. > Our page cache won’t allocate much more memory than what can fit the data in > your store files, so if your store is about 80G, then that explains why it > doesn’t consume more memory than that. > If you are using Linux, there might be a note in dmesg about high memory > usage, or there might not. “Map failed” isn’t a very informative error > message either way. > > -- > Chris Vest > System Engineer, Neo Technology > [ skype: mr.chrisvest, twitter: chvest ] > > >> On 04 Apr 2016, at 18:32, Zhixuan Wang <[email protected] >> <mailto:[email protected]>> wrote: >> >> I am using neo4j-2.3.3 and my java version is 1.8.0 >> >> So I am now creating an index on a label with 2.1 billion nodes, and >> encountered this error: >> >> Caused by: java.io.IOException: Map failed >> at sun.nio.ch.FileChannelImpl.map(Unknown Source) >> at >> org.apache.lucene.store.MMapDirectory$MMapIndexInput.<init>(MMapDirectory.java:270) >> at >> org.apache.lucene.store.MMapDirectory.openInput(MMapDirectory.java:220) >> at >> org.apache.lucene.index.CompoundFileReader.<init>(CompoundFileReader.java:65) >> at >> org.apache.lucene.index.SegmentCoreReaders.<init>(SegmentCoreReaders.java:75) >> at org.apache.lucene.index.SegmentReader.get(SegmentReader.java:116) >> at >> org.apache.lucene.index.IndexWriter$ReaderPool.get(IndexWriter.java:696) >> at >> org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:4368) >> at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3908) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:388) >> at >> org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:456) >> Caused by: java.lang.OutOfMemoryError: Map failed >> at sun.nio.ch.FileChannelImpl.map0(Native Method) >> >> It looks like there is not enough memory to handle that many indexes. >> My server has 160G of memory, and I have explicitly set >> "dbms.pagecache.memory=140g" in my neo4j.properties. However, I noticed that >> the actual memory usage of my neo4j process never exceeded 80G. >> >> I'm wondering if there is any other memory limit in the neo4j/java settings >> that prohibits using more than 50% of the actual memory? >> Or, it may be caused by some other error? >> >> Thanks, >> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Neo4j" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] >> <mailto:[email protected]>. >> For more options, visit https://groups.google.com/d/optout >> <https://groups.google.com/d/optout>. > -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
