io.mindmaps.graql.internal.gremlin.FragmentPriority Maven / Gradle / Ivy
/*
* MindmapsDB - A Distributed Semantic Database
* Copyright (C) 2016 Mindmaps Research Ltd
*
* MindmapsDB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* MindmapsDB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with MindmapsDB. If not, see .
*/
package io.mindmaps.graql.internal.gremlin;
/**
* represents the priority of a {@code Fragment}.
*
* Higher priority patterns are expected to be more efficient and better filter the query and are executed first.
*/
public enum FragmentPriority {
/**
* Looking up things by value. Values are non-unique so this is only slightly slower than lookup by ID
*/
VALUE_SPECIFIC,
/**
* Looking up by ID.
* Because types are often super-nodes and are usually referred to by ID, it is usually better to start from an
* instance (looked up by value) than from a type (looked up by ID) if possible.
*/
ID,
/**
* Looking up things by non-specific values. This includes predicates (e.g. 'value > 100') and very short strings,
* which are assumed to be common.
*/
VALUE_NONSPECIFIC,
/**
* Moving along an edge, where a concept can be expected to have at most one (e.g. ISA, AKO)
*/
EDGE_UNIQUE,
/**
* Moving along an edge, where a concept can be expected to have a small number bounded by the ontology
* (e.g. PLAYS_ROLE, HAS_ROLE)
*/
EDGE_BOUNDED,
/**
* Moving along a relation edge, where a concept can be expected to have a large number of relations.
*/
EDGE_RELATION,
/**
* Moving along an edge that a concept may have a HUGE number of, e.g. all instances of a type
*/
EDGE_UNBOUNDED,
/**
* Confirming that castings are all distinct
*/
// TODO: Should this have higher priority?
DISTINCT_CASTING;
}