JP2000222228A - Deadlock preventing method by verification of resource occupation order - Google Patents

Abstract

PROBLEM TO BE SOLVED: To verify the access order of resources in a test process and to pre vent a deadlock in actual operation by tracing the history of resource occupation and inputting the result to an access order verification tool of differently generat ed resources. SOLUTION: A device comprises a processor 101 which conducts a system test of an operation program and a processor 108 which verifies access order. The operation program 102 codes a process for obtaining trace information 103 right after a process for occupying a resource. The processor 108 which verifies occupation order inputs trace information 104 and an occupation order rule table 105 to the occupation order verifying tool 106 to obtain a verification result 107. The occupation order of resources can be confirmed and order illegality can mechanically be detected. Further, the resource access order verifying tool can be generated independently of a program main body and exerts no influence on the development process of the program main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a multitask environment in which one transaction occupies a plurality of resources, such as an online transaction processing system.

[0002]

2. Description of the Related Art In Japanese Unexamined Patent Application Publication No. 7-121587, "Method for Preventing Deadlock in Exclusive Control"
This is a method in which the resource access order is checked on the side.

[0003] This method is based on the premise that all resource accesses including database access are managed by one OCP.

In recent years, due to the international standardization and the spread of distribution package software, OCP software and database software are generally applied in combination with those generally available as package software, and the above methods cannot be applied. is there.

[0005] Checking the resource access order in a business program imposes a heavy burden on development, and it is not unlikely that adverse effects on the original processing will occur.

[0006]

In order to prevent deadlock, a resource occupation order is determined, and the order is strictly adhered to.
You have to write a program.

However, there is a problem that the order is not maintained due to a human error or the like, which causes a deadlock.

An object of the present invention is to verify the access order of resources in a test process and prevent deadlock from occurring in actual operation.

[0009]

Generally, in an online system program, trace information is output to a file in order to make it easy to confirm a test result and investigate when a failure occurs.

[0010] By tracing the history of resource occupation therein and inputting the trace to a resource access order verification tool created separately, it is possible to extract an illegal resource access order.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

First, an overall system configuration diagram is shown in FIG.

A processing apparatus 101 for performing a system test of a business program and a processing apparatus 108 for verifying an access order
Consists of The business program 102 codes a process of acquiring the trace information 103 immediately after the process of occupying the resource. The processing unit 108 for verifying the occupation order uses the trace information 104 and the occupation order rule table 105 as inputs to the occupation order verification tool 106.
The verification result 107 is obtained.

As shown in FIG. 3, the occupation order rule table 105 stores the occupation order (301) for each resource ID (302).
Is defined.

Next, FIG. 4 shows an example of trace acquisition information.

The transaction ID (401) is an identifier assigned for each transaction, and the time (402) is the actual time of the occupation request.

In the trace file, trace information of a plurality of transactions operating simultaneously is mixed and output. Since the verification of the occupation order needs to be performed for each transaction ID, the verification input is performed using the transaction ID (401) and the time (402) as keys.

Transaction ID (411) after sorting
Each unit is a verification unit (410).

The module name (403), the function name (404), and the line number (405) are information for recognizing the occupied resource in the business program.

The resource ID (406) indicates an occupied resource. For the trace information having the same transaction ID (401), it must be verified that the resource ID (406) is in the order specified in the occupation order rule table 105.

Next, an example of the processing flow of the occupation order verification tool will be described with reference to FIG.

(Step 201) The occupation order table file is read into a table on the memory.

(Step 202) An initial information save area for checking the ascending order of the occupation order number is initialized.

(Step 203) Sorted trace records are input one by one.

(Step 204) Repeat until the trace record ends.

(Step 205) From the resource ID 406 on the trace record, the occupation order rule table (302)
To retrieve the occupation order number (301) and add it to the trace information (507 in FIG. 5).

(Step 206) Transaction ID
Is changed, the order of the records is not checked, and the process branches to step 209.

(Step 207) The ascending order number is checked in ascending order.

(Step 208) If the order is not ascending, a warning message is added (507 in FIG. 5) (Step 20).
9) The trace information record to which the occupation order number 507 and the warning message 508 are added is output to the verification result file.

(Step 210) The current trace information record is saved in the immediately preceding information save area for checking the ascending order of the occupation order number.

FIG. 5 shows an example of the verification result. Access part that violates the rule, that is, the resource CC in the rule
Where an access should be made in the order of C → DDD, and for an access in which the order is reversed, the occupation order number (50
7) is not in ascending order.

As a deadlock factor, a warning message (508) is added and output.

[0033]

According to the present invention, the following effects can be expected.

(1) The occupation order of the resources can be confirmed, and the improper order can be mechanically detected.

(2) The resource access order verification tool can be created independently of the program body.
Does not affect the program development process.

(3) The deadlock prevention method is optimal for a system in which performance is emphasized because a load is not applied to the program body in terms of performance and resources.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is a flowchart of an access order verification tool.

FIG. 3 is a diagram showing an example of a table describing an access order rule.

FIG. 4 is a diagram showing an example of trace information acquired at the time of a test.

FIG. 5 is a diagram showing an example of a verification result by an access order verification tool.

[Explanation of symbols]

Reference numeral 101: a processing apparatus for performing a system test of a business program; 102, a business program; 103, trace information output when a test is executed; 104, trace information to be input for verification; 105, an occupation order rule table;
... Occupation order verification tool, 107 ... Verification result output file, 108 ... Processing device for verifying occupation order, 301 ... Occupation order number on occupation order rule table, 302 ... Resource ID on occupation order rule table, 401 ... Trace information Transaction ID, 402: time on trace information, 403: module name on trace information,
404: Function name on trace information, 405: Line number on trace information, 406: Resource I on trace information
D, 410: verification unit of trace information, 411: transaction ID on the trace information (after sorting), 501
... Transaction ID on verification result output file, 5
06: Resource ID on verification result output file, 507
... Occupation order number on verification result output file (added by verification tool), 508... Warning message on verification result output file (added by verification tool), 510... Verification unit on verification result output file.

Claims (1)

[Claims] In a multi-task online transaction processing system that accesses a large number of resources in one transaction, the occupation order rules of resources occupied by a transaction are verified from a trace file at the time of execution, and the improper order is extracted. A method for preventing deadlock in exclusive control, wherein the existence of a deadlock factor is detected in advance.