My Neo4j index has over 1.4M entries. My queries are running very slow. I have cached most of the database. However, now I have found that lot of disk read of the lucene index are taking place.
Per this article following code will help witch caching the index.
Index<Node> index = graphDb.index().forNodes( "actors" );
((LuceneIndex<Node>) index).setCacheCapacity( "name", 300000 );
Anyway I can do it via Neo4jClient? I have got so far as
var indexes = _graphClient.GetIndexes(IndexFor.Node);
var index = indexes.ElementAt(0);
But then it does not give me an option to set the cache capacity. Any thoughts how I can set the cache parameters via Neo4jClient or reduce the index look up time? TIA.
Neo4jClient works via the REST API. The behaviour you are describing is from the native Java API, and not exposed via the REST API. There is no way to do this via Neo4jClient, or any other REST based driver. You may be able to do it via config instead.
Related
I am trying to use the below API to get the list of docker images so that I could populate the dropdown on Jenkins build. Is there a way that this could be listed in a reverse chronological order rather than alphanumerical so that the newest image is at the top ? Thanks.
/artifactory/api/docker/repo/v2/image/tags/list
You will have to take help of Artifactory AQL query language.
An example AQL fragment is...
items.find({"repo":{"$eq":"<repositoryname>"}, "name":{"$eq" : "<artifactoryItemName>"}}) .sort({"$desc" : ["created"]})
The descending sort order is specified with $desc sort operator on the timestamp field created.
You can also limit the number of results returned by adding an extra limit to the above query...
items.find({"repo":{"$eq":"<repositoryname>"}, "name":{"$eq" : "<artifactoryItemName>"}}) .sort({"$desc" : ["created"]}).limit(10)
The AQL needs to be submitted at /artifactory/api/search/aql.
The same can be done via REST API as well with a POST request. The content should be posted not as a JSON but directly in the way query is specified as-is as text. The header for content type is Content-Type:text/plain. You can use the Basic authentication or other supported authentication methods.
There are a ton of things you can do with AQL. The syntax can look a bit confusing to begin with.
I would like to build an in-memory Lucene index from a collection of node properties and then search against that index.
These search transactions will be happening in parallel, I need to be able to construct a separate search index for each transaction. It seems like this would not be possible using native (manual) Neo4j indexes, since they are "global", hence the use of a memory-based search index, am I mistaken?
This is working great for our use case. A couple of notes:
Use MemoryIndex rather than RAMDirectory.
Be sure to specify "provided" in your dependencies for Lucene.
You can only use 5.5.0, which is what is used natively by Neo4j.
I am using node.js to connect to the neo4j database. Whenever I have to set an index for a node, I do it manually by going to the neo4j browser (localhost:7474).
CREATE INDEX ON :user(username)
First of all to be clear, this is an automatic index? Any changes or additions to :user are automatically maintained? Let me know if I am wrong.
If so, how does full text index work on neo4j? Is it the same process and neo manages automatically? For example does the following create full text index? Or we need to do something else?
CREATE INDEX ON :user(aboutme)
I built my own nodejs adapter to connect to neo4j, and so I only have access to cypher queries at the moment. To create an index I only have access to cypher or the browser (7474). So what is the proper way to create automatic fulltext index, preferably from the browser itself? And how do I access it using the cypher (or do I have to access it? does neo automatically figure out what index to use?). Online documentation and tutorials are a bit complicated for beginners :/ .
(I want to be able to do text search on the :user(aboutme) property)
If you want a full text index (where you can use the index to match on parts of the string and not the full, exact string), that isn't currently supported by the new cypher automatic indexes (like CREATE INDEX ON :user(username)). To do that you need to use what are called the legacy indexes. These use lucene under the covers and are much more powerful, but I believe they will eventually go away once that same functionality is supported with the new indexes.
Personally for full-text search I prefer using something like elasticsearch as it is easier to set up and use.
I want to play with neo4j and spacial indexes. I can't find any documentation that demonstrates how to do this through cypher, only through the REST API.
Is it possibly to create spacial indexes through Cypher, say in the neo4j web console?
There is currently no way to create a spatial index using Cypher. You can either use java API or a REST call, see docs at http://neo4j-contrib.github.io/spatial/#rest-api-create-a-spatial-index for details. Since Neo4j browser allows to send HTTP POST you can type there:
:POST /db/data/index/node {"name":"geom", "config":
{"provider":"spatial", "geometry_type":"point", "lat":"lat", "lon":"lon"}
}
Alternatively you can use the index command within neo4j-shell.
Update for Neo4j 3.0
Neo4j Spatial for 3.0 provides stored procedures to manage the spatial index - and therefore everything can be done through cypher. See https://github.com/neo4j-contrib/spatial/blob/master/src/main/java/org/neo4j/gis/spatial/procedures/SpatialProcedures.java.
Note: this version is not yet released, so you have to build from source yourself.
I've tried doing this with Umbraco 6.1.6. I've pretty much implemented what Drew did here: http://our.umbraco.org/forum/developers/extending-umbraco/23200-Lucene-with-spatialnet?p=0
I'm storing lat and long data in umbraco nodes. The nodes are being indexed as encided values with tiers. But, I am not returning any results when I add the DistanceFilter to the query.
I'm just wondering if anyone else has tried this and got it working. Perhaps you can post some code.
Thanks.
Josh,
Have you inspected the index using luke just to ensure that fields are there? Also have you tried running raw queries (get the generated query written out using code) on the index using luke?
Regards
Ismail