TECHNIQUES FOR RESOURCE DESCRIPTION FRAMEWORK MODELING WITHIN DISTRIBUTED DATABASE SYSTEMS

• US 20160371355A1
• Filed: 06/19/2015
• Published: 12/22/2016
• Est. Priority Date: 06/19/2015
• Status: Abandoned Application

• Current Assignee: NuoDB, Inc. (Dassault Systemes SA)
• Original Assignee: NuoDB, Inc. (Dassault Systemes SA)
• Inventors: Massari, Alberto, McNeill, Keith David, Abrevaya, Adam, Levin, Oleg, Proctor, Seth Theodore
• Application Number:
  US14/744,546
• Publication Number:
  US 20160371355A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2228 Indexing structures
• CPC Class Codes: G06F 16/25 Integrating or interfacing systems involving database management systems

Abstract

A Resource Description Framework engine is disclosed for performing transactional RDF-based operations against a distributed database. The RDFE manages a local memory cache that stores active portions of the database, and can synchronize those active portions using a transactionally-coherent distributed cache across all database nodes. During RDF reads, the RDFE can identify a triple-store table affected by a given RDF transaction, and can traverse the index objects for that table to locate triple values that satisfy a given RDF query, without intervening SQL operations. The RDFE can also perform SQL transactions or low-level write operations to update triples in triple-store tables. Thus the RDFE can update corresponding index objects contemporaneous with the insertion of RDF triples, with those updates replicated to all database nodes. A user application can instantiate the RDFE during runtime, thus allowing in-process access to the distributed database through which the user application can execute RDF transactions.

Claims

1. A system comprising:

a network interface circuit configured to communicatively couple to a communication network, the communication network comprising a plurality of database nodes forming a distributed database;

a memory for storing a plurality of database objects; and

a resource description framework (RDF) engine configured with an RDF mode, the RDF mode configured to;

parse a first RDF query, the first RDF query including at least one search pattern;

determine a directed graph to perform the first RDF query against, the directed graph being persisted in a relational database table;

identify a plurality of table index objects associated with the relational database table, each table index object including a key-value pair, wherein the plurality of table index objects forms a logical index structure; and

traverse the logical index structure to identify a value from a key-value pair that satisfies the at least one search pattern, and construct a result set including the identified value,

wherein traversing the logical index structure includes directly accessing table index objects in the memory without an intervening structured query language (SQL) operation.

2. The system of claim 1, wherein the first RDF query is received in response to a user application executing an application programming interface (API) function, and wherein the RDF mode is further configured to provide the constructed result set to the user application.

3. The system of claim 1, wherein the first RDF query is received from a hypertext transfer protocol (HTTP) endpoint configured to service Simple Protocol and RDF query Language (SPARQL) requests from a remote client, and wherein the RDF mode is further configured to provide the constructed result set to the remote client.

4. The system of claim 1, wherein the RDF mode is further configured to receive a replication message from a database node of the distributed database system, and wherein the replication message is configured to cause synchronization of database transactions such that a same database or portions thereof are stored in a memory within each of the plurality of database nodes.

5. The system of claim 4, wherein the replication message causes manipulation of a database object within the memory such that a new database object version is persisted in the memory, the new database object version representing a new triple inserted into the relational database table, and wherein the new triple is invisible to transactions until the RDF engine receives a commit message indicating a corresponding transaction was finalized.

6. The system of claim 1, wherein the logical index structure comprises at least one of a Balanced-tree structure, a Hash-based index and a doubly-linked list.

7. The system of claim 1, wherein the RDF mode implements Atomicity, Consistency, Isolation, and Durability (ACID) properties.

8. A computer-implemented method for executing RDF transactions against triple-store tables in a relational database, the method comprising:

parsing, by a processor, a first RDF query, the first RDF query including at least one search pattern;

determining, by the processor, a directed graph to perform the first RDF query against, the directed graph being persisted in a relational database table;

identifying, by the processor, a plurality of table index objects associated with the relational database table, each table index object including a key-value pair, wherein the plurality of table index objects forms a logical index structure; and

traversing, by the processor, the logical index structure to identify a value from a key-value pair that satisfies the at least one search pattern and constructing a result set with the identified value;

wherein traversing the logical index structure includes directly accessing table index objects in a memory without an intervening structured query language (SQL) operation.

9. The method of claim 8, wherein the first RDF query is received in response to a user application executing an application programming interface (API) function, and the method further comprising providing the constructed result set to the user application.

10. The method of claim 8, wherein identifying a plurality of table index objects further includes retrieving at least one table index object from a durable distributed cache, the durable distributed cache being implemented by a plurality of database nodes forming a distributed database.

11. The method of claim 10, the method further comprising receiving a replication message from a database node of a distributed database system, wherein the replication message is configured to cause synchronization of database transactions such that a same database or portions thereof are stored in a memory within each of the plurality of database nodes, and wherein the memory of each of the plurality of distributed database nodes collectively forms a portion of the durable distributed cache.

12. The method of claim 10, wherein the replication message causes manipulation of a database object within the memory such that a new database object version is persisted in the memory, the new database object version representing a new triple inserted into the relational database table, and wherein the new triple is invisible to database transactions until a commit message is received indicating a corresponding transaction was finalized.

13. The method of claim 8, wherein the logical index structure comprises a Balanced-tree structure, a Hash-based index and a doubly-linked list.

14. The method of claim 8, wherein the directed graph comprises a plurality of triple statements, each triple statement including a subject, a predicate and an object, and wherein each triple is stored in a relational database table based on its respective predicate.

15. A non-transitory computer-readable medium having a plurality of instructions encoded thereon that when executed by at least one processor cause a process to be carried out, the process configured to:

parse a first RDF query, the first RDF query including at least one search pattern;

determine a directed graph to perform the first RDF query against, the directed graph being persisted in a relational database table;

identify a plurality of table index objects associated with the relational database table, each table index object including a key-value pair, wherein the plurality of table index objects forms a logical index structure; and

traverse the logical index structure to identify a value from a key-value pair that satisfies the at least one search pattern and construct a result set with the identified value;

wherein traversing the logical index structure includes directly accessing the index objects in a memory without an intervening structured query language (SQL) operation.

16. The computer-readable medium of claim 15, wherein the first RDF query is received in response to a user application executing an application programming interface (API) function, and wherein the process is further configured to provide the constructed result set to the user application.

17. The computer-readable medium of claim 15, wherein the first RDF query is received from a hypertext transfer protocol (HTTP) endpoint configured to service Simple Protocol and RDF query Language (SPARQL) requests from a remote client, and wherein the process is configured to provide the constructed result set to the remote client.

18. The computer-readable medium of claim 15, wherein the plurality of table index objects are identified based on retrieving at least one table index object from a durable distributed cache, the durable distributed cache being implemented by a plurality of database nodes forming a distributed database.

19. The computer-readable medium of claim 18, wherein the process is further configured to receive a replication message from a database node of a distributed database system, and wherein the replication message is configured to cause synchronization of database transactions such that a same database or portions thereof are stored in a memory within each of the plurality of database nodes.

20. The computer-readable medium of claim 19, wherein the replication message manipulates a database object within the memory such that a new database object version is persisted in the memory, and wherein the new database object version is invisible to transactions until receiving a commit message indicating a corresponding transaction was finalized.