Hi all,

I’m running some scripts to solve a NP-problem in order to check trees compatibility and i’m using Basex as a database for my hierarchy structure, indeed for each path/each node i run a query on the basexserver.

This brings to have for a tree with 7 paths a 7! permutations and therefore at least 7!*4=21.000 queries (the query below) in a lapse of 5minutes.

If i use the db in my localhost environment i see that basexserver goes over 150% of cpu usage. I was wondering how to increase the performance without causing the server crash.

basex is running on a 2,6 GHz Intel Core i5 with 16gb of Ram, OS X 10.10.5

basex version is 8.2

Here the code i use:

public class BaseXOntologyManager{

private final int PORT; private final String PASSWORD; private final String USERNAME; private final String ADDRESS; private final String DBNAME;

/** * Constructor of the Basex ontology Manager * @param address The address of the DB * @param port The port to use to connect to the DB * @param username The username to use to connect to the DB * @param password The password to use to connect to the DB * @param dbName The db Name */ public BaseXOntologyManager(String address, int port, String username, String password, String dbName){//,boolean connected) { this.ADDRESS = address; this.PORT = port; this.USERNAME = username; this.PASSWORD = password; this.DBNAME = dbName; } private BaseXClient getOpenConnection() { try { BaseXClient session = new BaseXClient(this.ADDRESS, this.PORT, this.USERNAME, this.PASSWORD); return session; } catch (IOException e) { return null; } } /** * Return the subClasses of the element based on the ontology in the DB, * if the direct is true returns only the parents otherwise also the descendants * @param keyName The name of the Ontology to use * @param element the element to search in the param * @param direct true if you want only the parents * @return A list of subClasses of the ontology * @throws Exception when element doesn't belong to Ontology */ public ArrayList<String> getSubClasses(String keyName, String element, boolean direct) throws Exception { BaseXClient client = this.getOpenConnection(); if (client != null) { if(!checkExistence(element)) throw new Exception("notFound"+element); ArrayList<String> result = new ArrayList<String>(); String input = null;

if (direct == true) { input = "for $n in db:open('" + this.DBNAME +"', '/" + keyName + "')//*[parent::" + element + "] return $n/name()"; } else { input = "for $n in db:open('" + this.DBNAME +"', '/" + keyName + "')//*[ancestor::" + element + "] return $n/name()"; } try { final BaseXClient.Query query = client.query(input); while (query.more()) { result.add(query.next()); } query.close(); result.add(element);

return result;

} catch (IOException e) { return null; } finally { try { client.close(); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } }else{ System.out.println("CLIENT NULL"); } return null; }

Thanks, Filippo