Ultipa leverages an index mechanism to accelerate the retrieval of nodes and edges by creating index tree of node/edge properties in the disk, which is comparable to traditional databases. On top of that, Ultipa index also speeds up the filtering of nodes and edges in queries such as A-B and K-Hop.
Ultipa provides a native full-text search engine to break long text in node/edge properties, and conduct efficient and fast keyword search against the revert index of these word-segmentation results that are stored in the disk. It is suitable for various queries on graph from metadata query to A-B path, K neighbor and template queries.
Ultipa's LTE method is designed to improve the filtering speed of path and neighborhood queries by loading node/edge properties to the high-performance computing engine of Ultipa, after which the I/O of disk is tremendously reduced.
Index v.s. LTE
Index is similar to the path query acceleration mechanism LTE (Load to Engine), they both improve the query performance by consuming a certain amount of disk space and ensuring the created content can be persisted, but still, they differ in some aspects.
Diff 1：Acceleration Object
- LTE: the main acceleration object is path query, such as A-B query, K-Hop query. Any query that involves path (depth >= 1) is good to use LTE.
- Index: the main acceleration object is metadata query, ranging from querying for nodes and edges alone to filtering nodes and edges in paths.
Diff 2：Implementation Principle
- LTE: loads property index to Ultipa computing engine so that the engine can filter properties directly when querying, thus the dependency on disk-based I/O is lowered.
- Index: creates various index trees and uses data structures in the persistent storage, therefore the query that leverages index is accelerated and does NOT cast burden to memory.
Diff 3：Memory and Disk Usage
- LTE-ed property: primarily consumes memory, and the occupied space is determined by the number of values of the property; and the values are kept in disk(s) persistently for the automatic reloading after the reboot of instance.
- Index tree of index: primarily consumes disk space.
For properties that created index as well as LTE-ed:
- LTE is first used in path query
- General index is first used in metadata query