JPH0659915A - Method and device for controlling execution order of transaction - Google Patents

Abstract

PURPOSE:To execute the parallel processing of non-real time transaction without deteriorating the processing performance of a real time transaction being a main operation by applying time faster from completion time only by an estimated time and time later than current time only by the estimated time respectively to the real time transaction and the non-real time transaction as the execution priority of the transactions concerned. CONSTITUTION:A real time or non-real time transaction arriving at a system 11 is sent to a priority allocating part 12. On the other hand, a processing time estimating part 13 estimates processing time El based upon the reference or updating information of transactions. The allocating part 12 applies time (D1-E1) to the real time transaction 16 as its execution priority when the completion time of the transaction 16 is time D1. When the transaction arriving time of the non-real time transaction 17 is S1, the allocating part 12 applies time (S1+E1) to the transaction 17 as its execution priority.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transaction execution order control method and apparatus, and more particularly to a real-time transaction in which the value of processing is reduced or the processing becomes invalid unless the processing is completed by a designated completion deadline. In a system where non-real-time transactions that have no completion deadline but are completed in the shortest possible time are processed in parallel, without increasing the number of real-time transactions that cannot be completed before the completion deadline, The present invention relates to a transaction execution order control method and apparatus capable of shortening response time.

[0002]

2. Description of the Related Art There is a transaction in which the value of the processing is reduced or the processing becomes invalid unless the processing is completed by a designated completion deadline, and it is called a real-time transaction. The performance of the system that processes this real-time transaction is considered to be better as the number of transactions that do not meet the completion deadline decreases. In such a system, generally, the execution priority of a real-time transaction is determined based on the completion deadline, and the number of transactions that cannot meet the completion deadline is reduced as much as possible by advancing transaction processing in the order of execution priority. . As a method of determining the execution priority, an ED that gives a higher execution priority to a real-time transaction with a faster completion deadline
Method, estimate the time required to process a transaction,
Calculate the processing margin from the relationship between the completion deadline and the estimated time,
An LS method that gives higher execution priority to a real-time transaction with a short margin time is, for example, “Abbott, R., Gar.
cia-Molina, H.:"Scheduling Real-Time Transactions: a
Performance Evaluation ", Proceedings of the 14th V
LDB Conference, pp 1-12 (1988) ”. on the other hand,
In a system where real-time transactions are the main business, there is a demand for parallel execution of non-real-time transactions with no deadline, and non-real-time transactions can be processed in parallel without degrading the processing performance of real-time transactions. Is desired. Since the ED method and the LS method described above determine the execution priority based on the completion deadline of the real-time transaction, they cannot be applied to the non-real-time transaction having no completion deadline. Therefore,
To meet the above requirements, a mechanism for controlling the execution order of real-time transactions and non-real-time transactions is required. Here, a conventional method of transaction execution order control for parallel processing of non-real-time transactions without degrading the processing performance of real-time transactions will be described with reference to FIG. In FIG. 2, the real-time transaction 76 input to the system 71 is sent to the priority assigning unit 72. The priority assigning unit 72 determines the execution order priority of the real-time transaction 76 by the above-mentioned ED method or LS method, for example. At this time, if the LS method is used, the priority assignment unit 72 requests the processing time estimation unit 73 to estimate the processing time required for the real-time transaction 76. The processing time estimation unit 73 stores information about the number of data items to be referred to or updated by the real-time transaction 76 sent from the priority assignment unit 72, the average time required to refer to or update one data item sent from the transaction execution unit 75, and the like. Using the statistical information, the processing time required for the real-time transaction 76 is estimated and notified to the priority assigning unit 72. Priority allocation unit 7
Real-time transaction 7 given execution priority in 2
6 is sent to the execution order controller 74. On the other hand, system 7
The non-time transaction 77 input to 1 is directly sent to the execution order control unit 74. The transaction arriving at the execution order control unit 74 is sent to the transaction execution unit 75 and processed according to the following rules. When another real-time transaction R2 arrives at the execution order control unit 74 while the transaction execution unit 75 is processing the real-time transaction R1, the execution order control unit 74 executes the execution priority R1 of R2. R1 if higher than priority
The transaction execution unit 75 is requested to interrupt the processing and preprocess R2. At this time, the interrupted R1 is
After the execution priority is re-evaluated by the priority assigning unit 72, R2
The execution order control unit 74 waits for the completion of. If the priority of R2 is lower than the priority of R1, the execution order control unit 74 waits for the completion of R1 and requests the transaction execution unit 75 to process R2. When the non-real-time transaction N1 arrives at the execution order control unit 74 while the transaction execution unit 75 is processing the real-time transaction R1, the execution order control unit 74 waits for completion of R1 and waits for N1. The transaction execution unit 75 is requested to perform the above process. When another non-real time transaction N2 arrives at the execution order control unit 74 while the transaction execution unit 75 is processing the non-real time transaction N1, the execution order control unit 74 waits for the completion of N1. Request the transaction processing unit 75 to process N2.
If the execution order of transactions is controlled according to the above rules, real-time transactions are always prioritized over non-real-time transactions, and the execution order between real-time transactions is the same as when only real-time transactions are processed by the system. Therefore, non-real-time transactions can be processed in parallel without affecting the processing performance of real-time transactions.

[0003]

In the above prior art, even if a real-time transaction is executed after waiting for the completion of the non-real-time transaction, the real-time transaction precedes the non-real-time transaction even if the completion deadline is satisfied. Since it is processed, there is a problem that the response time of non-real time transaction is made longer than necessary. An object of the present invention is to determine the execution priority of real-time and non-real-time transactions in consideration of the relationship between the real-time transaction margin time and the non-real-time transaction processing time, and determine the real-time transaction margin time. By allocating as much as possible to the processing of non-real-time transactions, these problems can be improved,
It is an object of the present invention to provide a transaction execution order control method and apparatus capable of shortening the response time of a non-real time transaction without degrading the processing performance of the real time transaction.

[0004]

In order to achieve the above object, a transaction execution order control apparatus of the present invention is
A real-time transaction requested by specifying a completion deadline (for example, when referencing or updating the database),
A means for estimating the time required for transaction processing (processing time estimation unit) in a system that processes non-real-time transactions that are requested without specifying a completion deadline.
For real-time transactions, a time that is an estimated amount of time earlier than the transaction completion deadline, and for a non-real-time transaction, a time that is an estimated amount of time later than the current time, A means (priority assigning unit) that is given as an execution priority,
A means (execution order control unit) for controlling the execution order of transactions so as to preferentially process a transaction whose execution priority is given earlier, and a transaction selected based on an instruction from the execution order control means. And a means for processing (transaction execution unit). In addition, when determining the processing order of the real-time transaction and the non-real-time transaction, the execution order control unit obtains the latest time when the processing of the real-time transaction should be started and sets it as the execution priority of the non-real-time transaction. It is characterized in that a means for controlling the execution order of transactions is provided so that non-real-time transactions are processed with priority over real-time transactions only when the given time is earlier than the latest time. Further, in the transaction execution order control method of the present invention, when a transaction arrives at the system, the processing time estimation unit estimates the time required for processing the transaction, and the priority allocation unit determines the real-time transaction. A time that is earlier than the completion deadline by the estimated time and a time that is later than the current time by the estimated time is given to the non-real-time transaction as the execution priority of the transaction.
The execution order control unit is characterized by controlling to preferentially process a transaction whose time assigned as the execution priority is earlier. Further, at this time, by using the execution priority and the completion deadline given to the real-time transaction, all the completion deadlines of a plurality of real-time transactions to be processed in parallel are satisfied. The non-real-time transaction is given priority over the real-time transaction only when the latest time at which processing must be started is calculated and the time given as the execution priority of the non-real-time transaction is earlier than the latest time of the real-time transaction. It is characterized in that it is given to the transaction execution part.

[0005]

In the present invention, when a non-real-time transaction is processed in parallel in a system whose main task is real-time transaction, the non-transaction is processed by utilizing the margin time of the real-time transaction. For example, as shown in FIG. 3, if a real-time transaction R1 whose completion deadline is time D1 arrives at the system at time S1 and the processing time of R1 is estimated to be E1 by the processing time estimation unit, priority allocation is performed. The unit sets the execution priority of R1 to time D1-E1, that is, the latest time when the processing of R1 must be started to satisfy the completion deadline of R1. Next, if the non-real-time transaction N1 arrives at the system at time S2 and the processing time of N1 is estimated as E2 by the processing time estimation unit, the priority assignment unit determines the execution priority of N1 at time S2 + E2, that is, N1. It is the earliest time when the process of is completed. At this time, the execution order control unit D
1-E1 is earlier than S2 + E2, R1 is N1
If it waits for the completion of R1, it is judged that it cannot be completed by T1, and R1
Is controlled by the transaction execution unit in preference to N1. On the other hand, if the D1-E1 is later than S2 + E2, the execution order control unit R1
Determines that it can be completed by D1 even after waiting for the completion of N1, and controls the execution order so that N1 is processed by the transaction execution unit with priority over R1. Further, as shown in FIG. 4, a real-time transaction R1 having a completion deadline at time D1 and a real-time transaction R2 having a completion deadline at time D2 arrive at the system at times S1 and S2, and their respective processing times are processing times. E1 by the estimation department
And E2, the priority assignment unit determines that R1
The execution priority of R2 is D1-E1, and the execution priority of R2 is D2-
E2. At this time, the execution order control unit controls the execution order such that R1 having a higher execution priority is processed by the transaction execution unit with a higher priority than R2.
Of the completion deadline D1 of R2 is later than the execution priority D2-E2 of R2, and the latest time D2 at which processing of R1 must be started in order to satisfy both the completion deadlines of R1 and R2.
-E1-E2 is calculated. Next, when the non-real-time transaction N1 arrives at the system at time S3, the processing time of N1 is estimated to be E3 by the processing time estimation unit, and the priority assignment unit sets the execution priority of N1 to S3 + E3 If S3 + E3 is earlier than D2-E1-E2, the sequence control unit waits for completion of N1 and processes R1 and then R1 and R2.
It is determined that both of the completion deadlines are satisfied, and the execution order is controlled so that N1 is processed by the transaction execution unit with priority over R1. On the other hand, the execution order control unit S3 + E
If 3 is later than D2-E1-E2, when R1 is processed after waiting for the completion of N1, it is determined that at least one of the completion deadlines of R1 and R2 cannot be satisfied, and R1 gives priority to the transaction execution unit over N1. The execution order is controlled so that it is processed by. This makes it possible to further shorten the response time of non-real-time transactions without increasing the number of real-time transactions that cannot be completed by the completion deadline.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a transaction execution control device in an embodiment of the present invention. In FIG. 1, 11 is a system, 12 is a priority assigning unit, 13 is a processing time estimating unit, 14 is an execution order controlling unit, 15 is a transaction executing unit, and 16 is a system 11 which completes data reference or update. A real-time transaction 17 which designates and requests a deadline, and 17 is a non-real-time transaction which requests the system 11 to refer to or update data without designating a completion deadline. In this embodiment, the system 11
The real-time or non-real-time transaction that arrives at is sent to the priority assigning unit 12. Priority allocation unit 12
Requests the processing time estimation unit 13 to estimate the processing time required for the sent transaction. At this time, the priority assignment unit 12 notifies the processing time estimation unit 13 of the number of data to be referred to or updated in the transaction, as information necessary for the processing time estimation unit 13 to make the estimation. The processing time estimation unit 13 estimates the processing time required for the transaction based on the information sent from the priority assignment unit 12 and the transaction execution unit 15 that processes the transaction. For example, when the priority assigning unit 12 notifies the number d of data to be referred to or updated in the transaction and the transaction execution unit 15 notifies the average time u required to refer to or update one data, the process required for the transaction The time can be estimated as dxu. After being notified of the estimated time E1 by the processing time estimation unit 13, the priority assignment unit 12 determines the execution priority of the transaction as follows. That is, the priority allocation unit 12
Is the time D1 for the real-time transaction 16 when the completion deadline of the transaction is time D1.
-E1 is given as the execution priority. On the other hand, when the system arrival time of the transaction is S1 for the non-real-time transaction 17,
The time S1 + E1 is given as the execution priority. The priority assigning unit 12 sends the transaction to which the execution priority is given to the execution order control unit 14.

The execution order control unit 14 includes a priority assignment unit 12
The transaction execution unit 15 is requested to process the transaction sent from That is,
When the real-time transaction R1 is sent from the priority assigning unit 12, the execution order control unit 14 sends the real-time transaction R1 to the execution order control unit 14 that has not been completed and the completion deadline and execution of R1. From the relationship of priorities (501), the latest time L at which the real-time transaction R2 with the highest execution priority must be started in order to satisfy all the completion deadlines of these real-time transactions is obtained (502, 503). . This L is obtained by the procedure shown in FIG. 6, for example. That is, first, the real-time transaction R3 with the latest completion deadline is obtained (60
1), the execution priority of R3 is L (602, 60)
3). Next, a real-time transaction R4 with the next completion deadline after R3 is obtained (604, 605), and when the completion deadline of R4 is later than the current L, the estimated processing time of R4 is subtracted from the current L. The new time is set to L (60
6, 607, 603), and when the completion deadline of R4 is earlier than the current L, the completion deadline of R4 is set to a new L (606 to 608). When the above-described operation is repeated for all the real-time transactions in the order of the completion deadline, the finally obtained L becomes equal to the latest time when the real-time transaction R2 having the highest execution priority should be started. Next, when the transaction currently being processed by the transaction execution unit 15 is the real-time transaction R5 (504), the execution order control unit 14 compares the execution priority P1 of R1 with the execution priority P5 of R5 (50).
7) If P1 is earlier than P5, the transaction execution unit 15 is notified to interrupt the processing of R5 and perform the preceding processing of R1 (511). At this time, the execution order control unit 14 re-evaluates the interrupted execution priority of R5 using the priority assignment unit 12, and then re-determines L in the above-described procedure. On the other hand, if the time P1 is later than P5 in step 507, the execution order controller 14 causes R1 to wait in the execution order controller 14 (508). The execution order control unit 14 determines that the transaction currently being processed by the transaction execution unit 15 is a non-real time transaction N1.
(504), the execution priorities Q1 of L and N1 are compared (505). If L is earlier than Q1, the processing of N1 is interrupted and the real-time transaction R2 with the highest execution priority is preceded. The transaction execution unit 15 is notified to process (506). At this time, if R1 ≠ R2, the execution order control unit 14 sets R1 to the execution order control unit 1
4, the execution priority of the interrupted N1 is requested to the priority assigning unit 12 and re-evaluated. On the other hand, if L is later than Q1 in step 504, the execution order control unit 14 causes R1 to wait in the execution order control unit 14 (508).

When the non-real-time transaction N2 is sent from the priority assigning unit 13 (501, 502), the execution order control unit 14 compares the execution priority Q2 of N2 with the above L (509). , Q2 is earlier than L,
If the transaction currently being processed by the transaction executing unit 15 is the real-time transaction R5 (510), the transaction executing unit 15 is notified to interrupt the processing of R5 and preprocess N2 (51).
1). At this time, the execution order control unit 14 causes the interrupted R
After re-evaluating the execution priority of No. 5 using the priority allocation unit 12, L is calculated again by the procedure shown in FIG. On the other hand, if Q2 is earlier than L in step 509 and the transaction currently being processed by the transaction executing unit 15 is the non-real-time transaction N1 (510), the execution order control unit 14 sets Q2 to Q1. If the time is earlier (507), the transaction execution unit 15 is notified to interrupt N1 and perform prior processing on N2 (51).
1) When Q2 is later than Q1, N2 is made to wait in the execution order control unit 14 (508). At this time, the execution order control unit 14 requests the interrupted execution priority of N1 to the priority allocation unit 12 and re-evaluates it. Further, in step 509, if Q2 is later than L, the execution order control unit 14 causes N2 to wait in the execution order control unit 14 (508).

When the execution order control unit 14 is notified of the completion of the transaction by the transaction execution unit 15, the execution order control unit 1 requests the next transaction to the transaction execution unit 15 in the procedure shown in FIG.
Select from the transactions waiting in 4. That is, if the completed transaction is a real-time transaction, the execution order control unit 14 recalculates L according to the above procedure (701 to 703). Next, the execution order control unit 1
4 compares L with the execution priority Q3 of the non-real-time transaction N3 with the highest execution priority waiting (70
4) If Q3 is earlier than L, the transaction execution unit 15 is requested to process N3 (706). on the other hand,
If Q3 is later than L, the execution order control unit 14
The transaction executing unit 15 is requested to process the waiting real-time transaction with the highest execution priority (705). As a result, the transaction execution unit 15
Executes the transaction requested by the execution order control unit 14 and notifies the execution order control unit 14 of the completion of the process. In addition, when the transaction execution unit 15 is requested by the execution order control unit 14 for another transaction while processing a certain transaction, the transaction execution unit 15 interrupts the transaction currently being processed and precedes the requested transaction. To do. At this time, the transaction execution unit 15 notifies the execution order control unit 14 of information such as the number of remaining data to be referred to or updated in the transaction in order to reevaluate the execution priority of the interrupted transaction.

[0010]

According to the present invention, a non-real-time transaction has priority over a real-time transaction when the non-real-time transaction ends before the completion deadline even if the non-real-time transaction is processed before the real-time transaction. If a real-time transaction does not complete by the completion deadline when the non-real-time transaction is processed before the real-time transaction, the real-time transaction is processed with priority over the non-real-time transaction. Non-real-time transactions can be processed in parallel without degrading the processing performance of certain real-time transactions. Further, since the margin time of the real-time transaction processing can be utilized for the processing of the non-real-time transaction, the response time of the non-real-time transaction can be shortened as much as possible without affecting the performance of the real-time transaction.

[0011]

[Brief description of drawings]

FIG. 1 is a configuration diagram of a transaction execution control device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a transaction execution control device to which a conventional execution order control method is applied.

FIG. 3 is a diagram showing a transaction execution order control method in an embodiment of the present invention.

FIG. 4 is a diagram showing a transaction execution order control method according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a transaction execution order control procedure in an embodiment of the present invention.

FIG. 6 is a flowchart showing a transaction execution order control procedure in an embodiment of the present invention.

FIG. 7 is a flowchart showing a transaction execution order control procedure in an embodiment of the present invention.

[Explanation of symbols]

 11 System 12 Priority Assignment Section 13 Processing Time Estimating Section 14 Execution Order Control Section 15 Transaction Execution Section 71 System 72 Priority Assignment Section 73 Processing Time Estimation Section 74 Execution Order Control Section 75 Transaction Execution Section

Claims (4)

[Claims] 1. A means for estimating a time required for transaction processing in a system for concurrently processing a real-time transaction requested by specifying a completion deadline and a non-real-time transaction requested by not specifying a completion deadline, For real-time transactions, a time that is earlier than the completion deadline by the estimated time, and for non-real-time transactions, a time that is later than the current time by the estimated time is the execution priority of the transaction. A means for giving, a means for controlling the execution order of transactions so as to preferentially process a transaction with a time earlier given as the execution priority, and a transaction selected based on an instruction from the execution order control means. Transaction execution sequence control, characterized by comprising processing means apparatus. 2. The execution order control means obtains the latest time to start the processing of the real-time transaction when determining the processing order of the real-time transaction and the non-real-time transaction, and executes the non-real-time transaction. A means for controlling the execution order of the transactions is provided so that the non-real-time transaction is processed with priority over the real-time transaction only when the time given as the priority is earlier than the latest time. Item 1. A transaction execution order control device according to item 1. 3. A transaction execution order control method for a system that performs parallel processing of a real-time transaction requested by specifying a completion deadline and a non-real-time transaction requested by not specifying a completion deadline. When it arrives at the system, it estimates the time required to process the transaction. For real-time transactions, the estimated time is earlier than the completion deadline, and for non-real-time transactions, it is the estimated time. A method of controlling transaction execution order is characterized in that a time later than the current time is given as an execution priority of the transaction, and a transaction having an earlier time given as the execution priority is preferentially processed. 4. The non-real time is calculated only when the latest time to start the processing of the real-time transaction is calculated, and the time given as the execution priority of the non-real-time transaction is earlier than the latest time of the real-time transaction. 4. The transaction execution order control method according to claim 3, wherein the transaction is processed with priority over the real-time transaction.