You don't need to open multiple instances. Simply share the instance across
threads - it is thread safe.
-Original Message-
From: user-boun...@lists.neo4j.org [mailto:user-boun...@lists.neo4j.org] On
Behalf Of paolo.forte
Sent: Wednesday, July 27, 2011 9:14 AM
To: user@lists.neo4j.org
Subject: [Neo4j] Concurrent access to Index
Hello,
I'm testing neo4j (1.4) with a massive and continuous process: I have an
instance of EmbeddedGraphDatabase where each node must be unique (a node
identify a userid). My current problem is that when I try to open another
instance of graphdb with EmbeddedReadOnlyGraphDatabase in order to query the
graph (meanwhile the first instance is still inserting new data) I experienced
the following error: Exception in thread main
java.lang.reflect.InvocationTargetException at
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601) at
org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)Caused
by: java.lang.RuntimeException: java.io.FileNotFoundException:
/data/neo4j/metadata.db/index/lucene/node/users_id/_22j1m.cfs (No such file or
directory) at
org.neo4j.index.impl.lucene.LuceneDataSource.getIndexWriter(LuceneDataSource.java:601)
at
org.neo4j.index.impl.lucene.LuceneDataSource.getIndexSearcher(LuceneDataSource.java:484)
at org.neo4j.index.impl.lucene.LuceneIndex.query(LuceneIndex.java:248) at
org.neo4j.index.impl.lucene.LuceneIndex.get(LuceneIndex.java:187) at
nosql.metadata.test.Neo4JQueryTest.main(Neo4JQueryTest.java:117) ... 5
moreCaused by: java.io.FileNotFoundException:
/data/neo4j/metadata.db/index/lucene/node/users_id/_22j1m.cfs (No such file or
directory) at java.io.RandomAccessFile.open(Native Method) at
java.io.RandomAccessFile.init(RandomAccessFile.java:233) at
org.apache.lucene.store.SimpleFSDirectory$SimpleFSIndexInput$Descriptor.init(SimpleFSDirectory.java:69)
at
org.apache.lucene.store.SimpleFSDirectory$SimpleFSIndexInput.init(SimpleFSDirectory.java:90)
at
org.apache.lucene.store.NIOFSDirectory$NIOFSIndexInput.init(NIOFSDirectory.java:91)
at org.apache.lucene.store.NIOFSDirectory.openInput(NIOFSDirectory.java:78)
at
org.apache.lucene.index.CompoundFileReader.init(CompoundFileReader.java:66)
at
org.apache.lucene.index.CompoundFileReader.init(CompoundFileReader.java:55)
at org.apache.lucene.index.IndexWriter.getFieldInfos(IndexWriter.java:1193)
at
org.apache.lucene.index.IndexWriter.getCurrentFieldInfos(IndexWriter.java:1213)
at org.apache.lucene.index.IndexWriter.init(IndexWriter.java:1149) at
org.neo4j.index.impl.lucene.LuceneDataSource.getIndexWriter(LuceneDataSource.java:588)
... 9 more
I can recover the db index renaming the index segment (probably with loss of
data) and try to recover it with CheckIndex
Probably is my lack on knolodge on lucene indexing, but how can I (MULTIPLE)
query in safe way the db without corrupting the lucene index segments?
I also noted that if I start the server in read only mode (in order to connect
to an EmbeddedGraphDatabase that continuously ingest new data) the webadmin
interface doesn't update the number of nodes, edges and relationships are
the two problems correlated?
Thanks in advance for any suggestions and help.
Paolo Forte
As a matter of fact I would like to understand how it is possible to write and
read (query in read only mode) the db.
___
Neo4j mailing list
User@lists.neo4j.org
https://lists.neo4j.org/mailman/listinfo/user
___
Neo4j mailing list
User@lists.neo4j.org
https://lists.neo4j.org/mailman/listinfo/user
