JOIN OPERATIONS FOR CONTINUOUS QUERIES OVER ARCHIVED VIEWS

• US 20140095471A1
• Filed: 09/25/2013
• Published: 04/03/2014
• Est. Priority Date: 09/28/2012
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Deshmukh, Unmesh Anil, Srinivasan, Anand, Shukla, Vikram, Kali, Prathab
• Granted Patent: US 9,262,479 B2
• Time in Patent Office: Days
• US Class Current: 707/714
• CPC Class Codes: G06F 16/2308 Concurrency control transaction processing G06F9/466
• CPC Class Codes: G06F 16/24542 Plan optimisation
• CPC Class Codes: G06F 16/24544 Join order optimisation
• CPC Class Codes: G06F 16/24568 Data stream processing; Continuous queries
• CPC Class Codes: G06F 16/951 Indexing; Web crawling techniques

Abstract

A continuous query may be received, the continuous query being identified based at least in part on an archived view. The archived view may be created and/or identified based at least in part on a join query related to two or more archived relations associated with an application, at least one of the two or more archived relations being identified as a dimension relation. A query plan for the continuous query may be generated. A join operator in the query plan may be identified based at least in part on the dimension relation. A state of an operator corresponding to the dimension relation may be initialized. It may be identified if the state of the operator identifies an event that detects a change to the dimension relation. The continuous query may be re-started based at least in part on the event that detects the change to the dimension relation.

Claims

1. A computer-implemented method, comprising:

receiving, by a computer system configured to execute computer-executable instructions, a continuous query, a continuous query, the continuous query being identified based at least in part on an archived view;

creating the archived view, the archived view being identified based at least in part on a join query related to two or more archived relations associated with an application, at least one of the two or more archived relations being identified as a dimension relation;

generating a query plan for the continuous query;

identifying a join operator in the query plan, the join operator being identified based at least in part on the dimension relation;

initializing a state of an operator corresponding to the dimension relation;

identifying if the state of the operator identifies an event that detects a change to the dimension relation; and

re-starting the continuous query based at least in part on the event that detects the change to the dimension relation.

2. The computer-implemented method of claim 1, further comprising identifying a view root operator in the archived view, the view root operator being identified based at least in part on the join operator.

3. The computer-implemented method of claim 2, further comprising:

identifying a query operator in the query plan that topologically precedes the view root operator;

constructing an archiver query for the identified query operator that topologically precedes the view root operator;

executing the archiver query to obtain a result set of data records related to the application; and

generating a snapshot output of one or more data values related to the application based at least in part on the result set of data records related to the application.

4. The computer-implemented method of claim 3, further comprising initializing a state of the query operator based at least in part on the result set of data records.

5. The computer-implemented method of claim 4, further comprising generating the snapshot output of one or more data values related to the application based at least in part on the state of the identified query operator.

6. The computer-implemented method of claim 2, further comprising:

traversing the query plan in topological order to identify the view root operator, the view root operator being identified by an output operator to store event information related to the application;

inserting a buffer operator between the view root operator and the output operator in the query plan; and

storing the event information from the view root operator in the buffer operator.

7. The computer-implemented method of claim 6, further comprising:

identifying a second query operator in a second continuous query concurrently executing as being the same type as the query operator identified in the query plan, the second continuous query being identified based at least in part on the archived view; and

generating a combined query plan based at least in part on the query operator identified in the query plan being the same type as the second query operator in the second continuous query.

8. A computer-readable storage medium storing computer-executable instructions that, when executed by one or more computer systems, configure the one or more computer systems to perform at least:

instructions that cause the one or more processors to create an archived view, the archived view being identified based at least in part on a join query related to two or more archived relations associated with an application, at least one of the two or more archived relations being identified as a dimension relation;

instructions that cause the one or more processors to identify a join operator in the join query defining the archived view, the join operator being identified based at least in part on the dimension relation;

instructions that cause the one or more processors to initialize a state of an operator corresponding to the dimension relation;

instructions that cause the one or more processors to identify if the state of the operator identifies an event that detects a change to the dimension relation; and

instructions that cause the one or more processors to re-start the continuous query based at least in part on the event that detects the change to the dimension relation.

9. The computer-readable storage medium of claim 8, further comprising instructions that cause the one or more computer systems to identify a view root operator in the archived view, the view root operator being identified based at least in part on the join operator.

10. The computer-readable storage medium of claim 8, further comprising:

instructions that cause the one or more computer systems to generate a query plan for the continuous query;

instructions that cause the one or more computer systems to identify a query operator in the query plan that topologically precedes the view root operator;

instructions that cause the one or more computer systems to construct an archiver query for the identified query operator that topologically precedes the view root operator;

instructions that cause the one or more computer systems to execute the archiver query to obtain a result set of data records related to the application; and

instructions that cause the one or more computer systems to generate a snapshot output of one or more data values related to the application based at least in part on the result set of data records related to the application.

11. The computer-readable storage medium of claim 10, further comprising:

instructions that cause the one or more computer systems to traverse the query plan in topological order to identify the view root operator, the view root operator being identified by an output operator to store event information related to the application;

instructions that cause the one or more computer systems to insert a buffer operator between the view root operator and the output operator in the query plan; and

instructions that cause the one or more computer systems to store the event information from the view root operator in the buffer operator.

12. The computer-readable storage medium of claim 10, further comprising instructions that cause the one or more computer systems to generate the snapshot output of one or more data values related to the application based at least in part on the state of the identified query operator.

13. The computer-readable storage medium of claim 8, further comprising:

instructions that cause the one or more computer systems to identify a second query operator in a second continuous query concurrently executing as being the same type as the query operator identified in the query plan, the second continuous query being identified based at least in part on the archived view; and

instructions that cause the one or more computer systems to generate a combined query plan based at least in part on the query operator identified in the query plan being the same type as the second query operator in the second continuous query.

14. The computer-readable storage medium of claim 8, further comprising instructions that cause the one or more computer systems to initialize a state of the query operator based at least in part on the result set of data records.

15. The computer-readable storage medium of claim 8, further comprising instructions that cause the one or more computer systems to at least display a snapshot output of one or more data values related to the application based at least in part on the result set of data records related to the application.

16. A system, comprising:

a memory storing a plurality of instructions; and

a processor configured to access the memory, wherein the processor is further configured to execute the plurality of instructions to at least;

receive a continuous query, the continuous query being identified based at least in part on the archived view;

create the archived view, the archived view being identified based at least in part on a join query related to two or more archived relations associated with an application, at least one of the two or more archived relations being identified as a dimension relation;

generate a query plan for the continuous query;

identify a join operator in the query plan, the join operator being identified based at least in part on the dimension relation;

initialize a state of an operator corresponding to the dimension relation;

identify if the state of the operator identifies an event that detects a change to the dimension relation; and

re-start the continuous query based at least in part on the event that detects the change to the dimension table.

17. The system of claim 16, wherein the processor is further configured to execute the plurality of instructions to at least:

identify a query operator in the query plan that topologically precedes the view root operator;

construct an archiver query for the identified query operator that topologically precedes the view root operator;

execute the archiver query to obtain a result set of data records related to the application; and

generate a snapshot output of one or more data values related to the application based at least in part on the result set of data records related to the application.

18. The system of claim 16, wherein the processor is further configured to execute the plurality of instructions to at least:

identify a second query operator in a continuous query concurrently executing as being the same type as the query operator identified in the query plan; and

generate a combined query plan based at least in part on the query operator identified in the query plan being the same type as the second query operator in the continuous query.

19. The system of claim 16, wherein the processor is further configured to execute the plurality of instructions to at least initialize a state of the query operator based at least in part on the result set of data records.

20. The system of claim 19, wherein the processor is further configured to execute the plurality of instructions to at least generate the snapshot output of one or more data values related to the application based at least in part on the state of the identified query operator.