How to rebuild Neo4j Lucene index? - Neo4j.rb

I am running on Neo4j (1.4) using Neo4j.rb gem (1.2.2) on Rails 3.1

I bumped into problem where neo4j index was corrupted that I cant run the database anymore, as mentioned in several forums like this I deleted the db/index dir and it worked. However I need to rebuild the index again.

I cou开发者_Python百科ld not find anywhere in the docs on how to rebuild the index, could anybody please help?

Thanks alot!

You should go into your database directory and remove

• Directory named index
• The file index.db

and later on traverse the hole set of nodes and edges, updating the properties of each node.

/purbon

My problem was similar - after upgrading to neo4j 1.5 (from 1.4) my indexes got corrupted. My case: I had two indexes:

• __types__ : for indexing the type of persisted objects (provided by spring-data-neo4j 2.0.0.RC1)
• User : for indexing the username field, so I could do lookups after them

This resulted in a major problem, where I could find all the nodes by their id, but could not do lookups after username, or list all objects of a certain type.

The fix ( I will provide java code, but the idea would be the same in other languages too):

/* begin a transaction */
Transaction tx = graphDatabaseService.beginTx(); 
/* for all nodes in the database */
for (Node node : graphDatabaseService.getAllNodes()) { 
    /* reconstruct the saved object based on the __type__ property on the node - the result is a class that was annotated with @NodeEntity */
    DefaultDbNode ddn = neo4jTemplate.createEntityFromStoredType(node,
            null);
    /* reindex this node, adding it to the __types__ index, with key "className" (it is used by spring-data-neo4j) with the value __type__ */
    graphDatabaseService.index().forNodes("__types__")
            .add(node, "className", node.getProperty("__type__")); 
    /* if the reconstructed object is a User object */
    if (ddn instanceof User) { 
        /* add it to the User index, with the key "username" (which is also the saved fields name) */
        graphDatabaseService.index().forNodes("User")
                .add(node, "username", node.getProperty("username")); 
    }
}
/* end transaction */
tx.success();
tx.finish();

Hope this helps you or someone out!

Thanks to all who tried to help. In my case I have successfully solved the problem by taking the following steps:

Step 1 Following the recommendation from Neo4j's Michael Hunger (via mailing list), I used a tool called checkindex to remove corrupt index entries Lucene and Solr's Checkindex

Step 2 Upon removal of corrupt index entries, the remaining problem is to build them so Lucene can start querying them again. This could simply be done using using Model.addindex(:index_name). Note that this operation needs to be wrapped within a Neo4j::Transaction. In my case I ran it on railsconsole but I suppose you could also code them within the rails app.

Example:

Neo4j::Transaction.run do
  User.all.each do |user|
    user.add_index(:first_name)
    user.add_index(:email)
    user.save
  end
end

Hope this could help others who face the same problems.

Cheers