Control of a distributed data grid layer in a federated database system

Patent metadata

Field	Value
Publication number	US-2016154847-A1
Application number	US-201314902987-A
Country	US
Kind code	A1
Filing date	Jul 8, 2013
Priority date	Jul 8, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

The invention is directed towards a database access coordination arrangement ( 23 ) in a federated database system ( 10 ) comprising applications (Ai, A 2 , A 3 ) that access databases ( 34 - 50 ) under the control of a number of query handlers ( 24 - 32 ), the database access coordinating arrangement providing a group of traffic distribution units ( 16 - 22 ), each having connections to corresponding query handlers, and a traffic control unit (TCU), which traffic control unit selects traffic distribution unit for a query (Qi) from an application (Ai) based on at least one connectivity map of the connections existing between traffic distribution units, query handlers and databases and connectivity states of connections between traffic distribution units and query handlers, and schedules the query to the selected traffic distribution unit for accessing a database.

First claim

1 . A database access coordination arrangement in a federated database system, the database system comprising applications configured to access databases under the control of a number of query handlers, each query handler being connected to a number of databases, the database access coordinating arrangement comprising a processor and a memory, said memory containing computer instructions executable by said processor whereby said database access coordination arrangement is operative to provide:
a group of traffic distribution units, each having connections to corresponding query handlers; and a traffic control unit, said traffic control unit being configured to:
select a traffic distribution unit for a query from an application based on at least one connectivity map of the connections existing between traffic distribution units, query handlers and databases and connectivity states of connections between traffic distribution units and query handlers; and
schedule the query to the selected traffic distribution unit for accessing a database.

2 . The database access coordination arrangement according to claim 1 , the traffic control unit being further configured to select a query handler for the query and to schedule the query also to the query handler.

3 . The database access coordination arrangement according to claim 1 , wherein the connectivity state of a connection depends on alive messages sent by a query handler to the corresponding traffic distribution unit.

4 . The database access coordination arrangement according to claim 3 , wherein the connectivity state of a connection is connected if alive messages are timely received and disconnected if they are not.

5 . The database access coordination arrangement according to claim 3 , wherein an alive message from a query handler comprises at least one load value of the query handler, and if the query is a write query, the traffic control unit is further configured to determine at least one load factor for the query and schedule the query based on the load factor of the query and corresponding load values of the traffic distribution units.

6 . The database access coordination arrangement according to claim 5 , wherein a traffic distribution unit is selected for the query which will balance the load between the traffic distribution units.

7 . The database access coordination arrangement according to claim 5 , wherein the load factor of the query is determined as a weighted average of loads of similar queries.

8 . The database access coordination arrangement according to claim 1 , wherein one of the traffic distribution units acts as the traffic control unit, each traffic distribution unit has an identity, where the identities are sequentially generated and assigned at instantiating, and a traffic distribution unit is configured to, in a traffic selection scheme, send the own identity to the other traffic distribution units, receive the identities of these other traffic distribution units, compare the own identity with the received identities and seize the role of traffic control unit if the own identity precedes the others in the sequence.

9 . The database access coordination arrangement according to claim 8 , wherein the traffic control unit is configured to periodically send alive messages to the other traffic distribution units, and a traffic distribution unit is configured to enter the traffic selection scheme, if no alive message is received from the traffic control unit within an alive message time limit.

10 . The database access coordination arrangement according to claim 1 , wherein a connectivity map is provided for each traffic distribution unit.

11 . A method for coordinating database access in a federated database system, the database system comprising applications configured to access databases under the control of a number of query handlers, each query handler being connected to a number of databases and to one or more traffic distribution units in a group of traffic distribution units, the method comprising:
selecting a traffic distribution unit for a query from an application based on at least one connectivity map of the connections existing between traffic distribution units, query handlers and databases and connectivity states of connections between traffic distribution units and query handlers; and scheduling the query to the selected traffic distribution unit for accessing a database.

12 . The method according to claim 11 , further comprising selecting a query handler for the query, wherein the scheduling comprises scheduling the query also to the query handler.

13 . The method according to claim 11 , wherein the connectivity state of a connection depends on alive messages sent by a query handler to the corresponding traffic distribution unit.

14 . The method according to claim 13 , wherein the connectivity state of a connection is connected if alive messages are timely received and disconnected if they are not.

15 . The method according to claim 13 , wherein an alive message from a query handler comprises at least one load value of the query handler, and if the query is a write query, further comprising determining at least one load factor for the query and scheduling the query to a traffic distribution unit based on the load factor of the query and corresponding load values of the traffic distribution units.

16 . The method according to claim 15 , wherein the selection of traffic distribution unit comprises selecting a traffic distribution unit for the query that will balance the load between the traffic distribution units.

17 . The method according to claim 16 , wherein the load factor of the query is determined as a weighted average of loads of similar queries.

18 . The method according to claim 11 , wherein one of the traffic distribution units acts as a traffic control unit performing said selection of traffic distribution unit, each traffic distribution unit has an identity, where the identities are sequentially generated and assigned at instantiating, the method further comprising, in each traffic distribution unit in a traffic selection scheme:
sending the own identity to the other traffic distribution units; receiving the identity of these other traffic distribution units; comparing the own identity with the received identities; and seizing the role of traffic control unit if the own identity precedes the others in the sequence, where the role of traffic control unit comprises the selecting of a traffic distribution unit for a query and scheduling the query to the selected traffic distribution unit.

19 . The method according to claim 18 , wherein the traffic control unit is configured to periodically send alive messages and the method further comprises entering the traffic selection scheme if no alive message is received from the traffic control unit within an alive message time limit.

20 . A computer program for coordinating database access in a federated database system, the database system comprising applications configured to access databases under the control of a number of query handlers, each query handler being connected to a number of databases and to one or more traffic distribution units in a group of traffic distribution units, the computer program comprising computer program code which when run in a database access coordination arrangement, causes the database access coordination arrangement to:
select a traffic distribution unit for a query from an application based on at least one connectivity map of the co

Assignees

• Ericsson Telefon Ab L M

Inventors

• Prasanna Kumar Manoj
• Shivashankar Subramanian

Classifications

• G06F16/24542 Primary

  Plan optimisation · CPC title

• G06F16/2471 Primary

  Distributed queries · CPC title

• G06F17/30545

  Physics · mapped topic

• G06F17/30463 Primary

  Physics · mapped topic