JP2004295272A - Transaction control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: unnecessary two-phase commitment is executed to a transaction manager and a resource manager in a distributed transaction processing system wherein a plurality of resource adapters each having no nonvolatile storage shares the single resource manager. <P>SOLUTION: When wrapping the resource adapter by a resource adapter wrapper and when referring to information showing a group of the resource adapters sharing the single resource manager to register the resource adapter into the transaction manager, the resource adapter is registered as a single transaction branch to make the transaction manager to execute one-phase commitment, a settlement process is distributed to the resource adapter from the resource adapter wrapper, and the resource manager is wrapped by a resource manager wrapper doing nothing in the settlement process such that the resource adapter does not repeatedly call the settlement process of the resource manager. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for optimizing one-phase commit in a distributed transaction system in which resource adapters without non-volatile storage share one resource manager.
[0002]
[Prior art]
Transactions are a concept introduced by many data processing systems. The transaction is a management unit for performing exclusive control of data processing, failure recovery, and the like by dividing the data processing sequence. One transaction is a processing sequence from when a transaction start instruction is issued in the middle of the processing sequence to when a transaction end instruction is issued. It is guaranteed that all the processing performed in the transaction has been performed or not performed at all. This makes it easy to guarantee data consistency.
[0003]
For example, when two records are updated in one database, one transaction is started by starting a transaction, updating two records, and ending the transaction. At this time, either the processing is successful and two records are always updated, or the processing fails and both records are not always updated. One record is updated and the other is updated. Transactions ensure that records are not updated. In any case, consistency between the two records is guaranteed.
[0004]
In order to realize the above example, the database accumulates the update information performed during the transaction in a buffer on the main memory, and at the time of issuing the transaction end instruction, writes the update information to the secondary memory at a time and fixes it. If a failure occurs in the middle, the update information is discarded, all updates are discarded, and it is determined that processing has not been performed.
[0005]
In the above example, the number of databases is one, but if there are a plurality of databases, further processing is required to perform transaction processing. For example, to update two records in two databases, start a transaction, update record 1 in database 1, update record 2 in database 2, and end the transaction to make one transaction. It is necessary to newly introduce a transaction manager that arbitrates transactions and perform the following processing. Each database stores update information performed during the transaction in a buffer on each main memory.
[0006]
When a transaction end instruction is issued, the transaction manager performs arbitration. First, the transaction manager instructs each database to write the update information of the database once to the secondary storage in a form that can be fixed or canceled. This process is called a prepare. Each database responds to the transaction manager whether the prepare was successful. If both databases are successfully prepared, the transaction manager writes the transaction log to secondary storage to determine that the transaction was successful.
[0007]
Next, the transaction manager instructs each database to determine the update of the database. This process is called a commit. Processing of the transaction end command is completed when each database responds to the transaction manager that the commit has been completed. Such a procedure of performing the transaction end processing in two stages of prepare and commit is called two-phase commit.
[0008]
In the two-phase commit process, a prepare was necessary to confirm whether all the update processes of a plurality of databases were successful. However, when there is only one database, there is no need to check a plurality of databases, so that the prepare can be omitted and the transaction manager can instruct to perform commit processing to the database. The commit process at this time is called a one-phase commit, and executing the one-phase commit is called a one-phase commit optimization. When the one-phase commit optimization is performed, the transaction manager does not need to write the transaction log to the secondary storage, and the performance is improved.
[0009]
As a model for performing such two-phase commit processing, a model described below is widely used (for example, see Non-Patent Document 1). In this model, the database of the above example is generalized to be called a resource manager, and the transaction of the above example is called a global transaction. Since there are a plurality of global transactions, they are distinguished by adding a unique identifier. This identifier is called a global transaction identifier. The target for which the transaction manager performs the two-phase commit process is an individual resource manager or a unit in which the resource managers are grouped. This unit is called a transaction branch. An identifier that distinguishes a transaction branch is called a branch qualifier.
[0010]
In this model, when the processing of the resource manager is performed as a transaction, the processing of the resource manager is performed after associating the resource manager with the transaction branch. This process is called association. The one-phase commit, prepare, and commit processes performed by the resource manager are collectively referred to as settlement. The association is made for each resource manager, but the settlement is made for each transaction branch. Therefore, when a plurality of resource managers are included in the transaction branch, the transaction manager selects any one of the resource managers and makes a decision. When a transaction includes one transaction branch, one-phase commit optimization is performed.
[0011]
[Non-patent document 1]
X / Open Snapshot Distributed Transaction Processing: The XA + Specification Version 2, X / Open Company Ltd. Pp. 1994. 3.
[0012]
[Problems to be solved by the invention]
In the present invention, a resource manager that has no nonvolatile storage and caches data of another resource manager is called a resource adapter. In a configuration in which multiple resource adapters share a single resource manager, only the single resource manager needs to actually write the update information to the secondary storage. There is no need to write the transaction log. In the conventional technology, when there are a plurality of resource adapters directly managed by the transaction manager, transaction branches are generated by the number of resource adapters and unnecessary two-phase commit processing is performed. Had been lowered.
[0013]
It is an object of the present invention to provide a method and apparatus that allows one-phase commit optimization in such cases.
[0014]
[Means for Solving the Problems]
In the present invention, the object of the present invention is achieved by the following procedure.
[0015]
Group and manage resource managers belonging to the same resource. The resource adapters are wrapped by a resource adapter wrapper, and the resource adapter wrappers of the resource adapters that use the resource managers belonging to the group are grouped so as to belong to a single transaction branch and registered in the transaction manager. Since there is a single transaction branch, one-phase commit optimization is performed. Since the settlement is performed for any one resource adapter included in the transaction branch, the call of the settlement processing is distributed to the resource adapters belonging to the group with reference to the group table of the resource manager group management unit. As a result, in order to prevent the resource manager's decision processing from being called twice, the corresponding resource manager for the resource adapter that calls the resource manager decision processing is wrapped by a resource manager wrapper that does nothing in the decision processing. Instead, the resource manager group management unit calls the settlement process of the settlement resource manager so that the settlement process is called only once.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a diagram showing a schematic configuration of the present embodiment.
[0018]
The transaction manager 100 includes a global transaction identifier GTRID101 item, a RAID102 item for identifying a resource manager, and a transaction branch qualifier BQUAL103 item, and the record 104 stores GTRID "T1", RAID "RAW1", BQUAL "B1", The record 105 stores GTRID "T1", RAID "RAW2", and BQUAL "B1", and the record 106 stores GTRID "T1", RAID "RAW3", and BQUAL "B1". The transaction manager 100 includes a resource registration procedure 107 for registering a resource adapter wrapper.
[0019]
The resource adapter wrappers RAW1 (110), RAW2 (115), and RAW3 (117) include an association procedure 111 and a settlement procedure 112. The association procedure 111 calls the association procedure of the corresponding resource adapter. The settlement procedure 112 includes one-phase commit processing, prepare processing, and commit processing, and refers to the table of the resource manager group management unit 130 to appropriately call the corresponding resource adapter's settlement procedure.
[0020]
The resource manager group management unit 130 includes a wrapper RAID item 131 for identifying a resource adapter wrapper, a decision item 132 for indicating whether or not it is necessary to call a resource adapter decision process, and a group 133 item for identifying a group. The record 135 stores “RAW1”, the result “unnecessary” and the group “G1”, the record 135 stores the wrapper RAID “RAW2”, the result “necessary” and the group “G1”, and the record 136 stores the wrapper RAID “RAW3” and the result “ Necessary "and group" G1 "are stored. The resource manager group management unit 130 includes a group 137 item for identifying the resource manager group and a settlement RMID 138 item for identifying the settlement resource manager, and the record 139 stores the group “G1” and the settlement RMID “RM4”.
[0021]
The resource adapter RA1 (140) includes an association procedure 141, a settlement procedure 142, and a usage RMID 143 item for identifying a resource manager to be used, and the record 144 stores a usage RMID “RM1”. Since the resource adapter RA1 (140) does not include data, there is no need to call the settlement procedure 142.
[0022]
The resource adapter RA2 (150) includes an association procedure 151, a settlement procedure 152, and a usage RMID 153 item for identifying a resource manager to be used, and the record 154 stores a usage RMID “RM2”. Since the resource adapter RA2 (150) includes the data 155 updated by the settlement procedure 152, it is necessary to call the settlement procedure 152.
[0023]
The resource adapter RA3 (160) includes an association procedure 161, a settlement procedure 162, and a used RMID 163 item for identifying a resource manager to be used, and the record 164 stores a used RMID "RMW1". Since the resource adapter RA3 (160) includes the data 165 updated by the settlement procedure 162, it is necessary to call the settlement procedure 162.
[0024]
The resource manager wrapper RMW1 (170) includes an association procedure 171, a settlement procedure 172, and a wrap destination RMID 173 item for identifying a wrap destination resource manager, and the record 174 stores the wrap RMID "RM3".
[0025]
The resource managers RM1 (180), RM2 (185), RM3 (186), and RM4 (187) belong to the same resource 190 and include an association procedure 181 and a settlement procedure 182.
[0026]
FIG. 2 is a diagram showing an embodiment when the resource 190 is a database. The resource managers RM1 (180), RM2 (185), RM3 (186), and RM4 (187) belonging to the resource 190 access the same database 210 through the database access control 200. The database access control 200 includes a GTRID 201 item for identifying a global transaction and a CID 202 item for identifying a database connection, and the record 203 stores GTRID “T1” and CID “C1”. This allows multiple resource managers to access a common resource.
[0027]
FIG. 3 is a diagram showing the configuration of the device.
[0028]
The computer 301 includes a main storage device 310, a secondary storage device 320, a CPU 380, a mouse 381, a display 382, a keyboard 383, a network interface 385, and a bus 370 interconnecting these. Then, the computer 301 is connected to the network 390 via the network interface 385. In the main storage device 310, the operating system 311, the transaction manager 100, the resource adapter wrappers RAW1 (110), RAW2 (115), RAW3 (117), the resource adapter group management unit 130, the resource adapters RA1 (140), RA2 (150) ), RA3 (160), resource manager wrapper RMW1 (170), resource manager RM1 (180) belonging to resource 190, RM2 (185), RM3 (186), RM4 (187), and database access control 200. . The secondary storage device 320 stores a database storage area.
[0029]
The details of the transaction processing procedure will be described with reference to FIGS. 4 to 8. At the start of a transaction, the transaction manager 100 calls the resource registration procedure 107 to register the resource adapter wrappers RAW1 (110), RAW2 (115), and RAW3 (117). This sequence is shown in FIG. The transaction manager 100 performs the processing shown in FIG. 5 at the end of the transaction, and performs one-phase commit optimization or two-phase commit processing. In this embodiment, it is assumed that the transaction manager 100 selects the resource adapter wrapper RAW1 (110) from the resource adapter wrappers RAW1 (110), RAW2 (115), and RAW3 (117) included in the transaction branch during the settlement processing. FIG. 6 shows a process performed by the resource adapter wrapper RAW1 (110) in the one-phase commit process, FIG. 7 shows a process performed by the resource adapter wrapper RAW1 (110) in the prepare process, and FIG. 8 shows a process performed by the resource adapter wrapper RAW1 (110) in the commit process. Processing to be performed.
[0030]
FIG. 4 is a flowchart showing the operation of the resource registration procedure 107. The resource registration procedure 107 receives a GTRID for identifying an active global transaction and a RAID for identifying a resource adapter to be registered.
[0031]
(Step 401) The search entry is positioned at the top of the table of the transaction manager 100.
[0032]
(Step 402) It is determined whether the search is completed.
[0033]
(Step 403) The group corresponding to the RAID to be registered and the group corresponding to the RAID 102 item of the search entry are compared with reference to the wrapper RAID 131 item and the group 133 item of the table of the resource adapter group management unit 130.
[0034]
(Step 404) In order to generate a new transaction branch, a new BQUAL is generated and set as a set BQUAL.
[0035]
(Step 405) It is determined whether the comparison result indicates a match.
[0036]
(Step 406) The search entry is advanced by one.
[0037]
(Step 407) The BQUAL of the current search entry is obtained and set as the set BQUAL.
[0038]
(Step 408) The GTRID, the RMID to be registered, and the set BQUAL are registered in the table of the transaction manager.
[0039]
FIG. 5 is a flowchart showing a transaction commit process performed by the transaction manager 100.
[0040]
(Step 501) The number of transaction branches included in the transaction to be committed is counted.
[0041]
(Step 502) It is determined whether the number of transaction branches is one.
[0042]
(Step 503) An arbitrary resource adapter wrapper is selected for each transaction branch, and all are prepared. In this embodiment, the resource adapter wrapper RAW1 (110) is selected and prepared.
[0043]
(Step 504) An arbitrary resource adapter wrapper is selected and one-phase commit is performed. In this embodiment, the resource adapter wrapper RAW1 (110) is selected and one-phase commit is performed.
[0044]
(Step 505) It is determined whether or not all are prepare success responses.
[0045]
(Step 506) An arbitrary resource adapter wrapper is selected for each transaction branch, and all commits are completed. In this embodiment, the commit is completed by selecting the resource adapter wrapper RAW1 (110).
[0046]
(Step 507) An arbitrary resource adapter wrapper is selected for each transaction branch, and all rollbacks are completed. In this embodiment, the rollback is completed by selecting the resource adapter wrapper RAW1 (110).
[0047]
FIG. 6 is a flowchart showing an operation in which the resource adapter wrapper RAW1 (110) performs one-phase commit.
[0048]
(Step 601) Receive a one-phase commit instruction.
[0049]
(Step 602) All resource adapters RA2 (150) and RA3 (160) that need to be settled in the group are prepared.
[0050]
(Step 603) It is determined whether or not all succeeded.
[0051]
(Step 604) Commit the settlement resource manager RM4 (187).
[0052]
(Step 605) Roll back the settlement resource manager RM4 (187).
[0053]
(Step 606) It is determined whether the commit of the settlement resource manager RM4 (187) is successful.
[0054]
(Step 607) Commit all resource adapters RA2 (150) and RA3 (160) required for settlement in the group.
[0055]
(Step 608) All resource adapters RA2 (150) and RA3 (160) that need to be settled in the group are rolled back.
[0056]
(Step 609) Return a one-phase commit success response.
[0057]
(Step 610) Return a one-phase commit failure response.
[0058]
FIG. 7 is a flowchart showing an operation in which the resource adapter wrapper RAW1 (110) performs a prepare.
[0059]
(Step 701) Receive a prepare instruction.
[0060]
(Step 702) All resource adapters RA2 (150) and RA3 (160) that need to be settled in the group are prepared.
[0061]
(Step 703) It is determined whether or not all succeeded.
[0062]
(Step 704) Prepare settlement resource manager RM4 (187).
[0063]
(Step 705) Rollback the settlement resource manager RM4 (187).
[0064]
(Step 706) It is determined whether or not the preparation of the settlement resource manager RM4 (187) is successful.
[0065]
(Step 707) All resource adapters RA2 (150) and RA3 (160) that need to be settled in the group are rolled back.
[0066]
(Step 708) Return a prepare success response.
[0067]
(Step 709) A prepare failure response is returned.
[0068]
FIG. 8 is a flowchart showing an operation in which the resource adapter wrapper RAW1 (110) performs a commit.
[0069]
(Step 801) Receive a commit instruction.
[0070]
(Step 802) It is determined whether the content of the commit instruction is a commit.
[0071]
(Step 803) Commit the settlement resource manager RM4 (187).
[0072]
(Step 804) The settlement resource manager RM4 (187) is rolled back.
[0073]
(Step 805) It is determined whether the commit of the settlement resource manager RM4 (187) is successful.
[0074]
(Step 806) Commit all resource adapters RA2 (150) and RA3 (160) that need to be settled in the group.
[0075]
(Step 807) Roll back all resource adapters RA2 (150) and RA3 (160) that need to be settled in the group.
[0076]
(Step 808) Return a commit success response.
[0077]
(Step 809) Return a commit failure response.
[0078]
【The invention's effect】
The present invention enables one-phase commit optimization when multiple resource adapters without persistent storage share a single resource manager.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an embodiment.
FIG. 2 is a diagram showing an embodiment when a resource 190 is a database.
FIG. 3 is a diagram illustrating a configuration of an apparatus according to the present embodiment.
FIG. 4 is a flowchart showing an operation of a resource registration procedure 107.
FIG. 5 is a flowchart showing a transaction commit process performed by the transaction manager 100.
FIG. 6 is a flowchart illustrating an operation in which a resource adapter wrapper performs one-phase commit.
FIG. 7 is a flowchart illustrating an operation in which a resource adapter wrapper performs a prepare.
FIG. 8 is a flowchart showing an operation performed by the resource adapter wrapper to perform a commit.
[Explanation of symbols]
100: transaction manager, 110, 115, 117: resource adapter wrapper, 130: resource adapter group management unit, 140, 150, 160: resource adapter, 170: resource manager wrapper, 180, 185, 186, 187: resource manager, 300 : Computer, 310: main storage, 311: operating system, 320: secondary storage, 370: bus, 380: CPU, 381: mouse, 382: display, 383: keyboard, 385: network interface, 390: network

Claims (3)

In a distributed transaction processing system comprising a transaction manager and a resource adapter that does not use secondary storage in transaction processing and the resource manager, wherein the transaction manager controls the resource adapter, the resource used by a plurality of resource adapters participating in a transaction A transaction control method for optimizing one-phase commit processing when a manager shares one resource,
A resource adapter group management unit that manages a group of the resource adapters that share the resource with a resource adapter wrapper that wraps the resource adapters,
The transaction manager has a correspondence table of a transaction, a registered resource adapter wrapper, a prepare in two-phase commit, and a transaction branch which is a processing unit of commit.
The resource adapter wrapper, the resource adapter, and the resource manager have an association process with the transaction branch, a one-phase commit process, a prepare process, and a commit process,
The resource adapter group management unit stores the resource adapter wrapper, information indicating whether or not the resource adapter wrapper wraps the resource adapter is necessary or not, a correspondence table of the group, and a correspondence table of the group and the settlement resource manager. Have
The information indicating whether or not the resource adapter settlement process is required is configured when the decision process of the corresponding resource adapter changes the internal state of the corresponding resource adapter, and is unnecessary when the internal state is not changed.
Registering the resource adapter corresponding to the same group as the same transaction branch when registering the resource adapter wrapper with the transaction manager;
Associating the transaction branch with the resource adapter wrapper registered with the transaction manager, and associating the transaction branch with the resource adapter wrapped by the resource adapter wrapper;
One arbitrary resource adapter wrapper is selected for each transaction branch registered in the transaction manager, and it is determined whether there is one transaction branch. If there is one, a one-phase commit process is performed on the resource adapter wrapper. Performing a prepare process and a commit process on the resource adapter wrapper when there are a plurality of transaction branches;
A one-phase commit process of the resource adapter wrapper belongs to the same group as the resource adapter wrapper and prepares the resource adapter that requires a settlement process, and a commit of the settlement resource manager corresponding to the same group as the resource adapter wrapper. Process, sequentially calling commit processing of the resource adapter which belongs to the same group as the resource adapter wrapper and requires a settlement processing,
The resource adapter wrapper prepare process belongs to the same group as the resource adapter wrapper, and the resource adapter prepare process requires the finalization process, the resource manager wrapper prepare process corresponding to the same group as the resource adapter wrapper, Calling in order,
The commit process of the resource adapter wrapper includes a step of sequentially calling a commit process of the settlement resource manager, and a commit process of the resource adapter that belongs to the same group as the resource adapter wrapper and requires a settlement process. Transaction control method. 2. The transaction control method according to claim 1, wherein when at least one of the prepare process and the commit process of the resource adapter calls the prepare process and the commit process of the resource manager used by the resource adapter, the resource manager wraps the resource manager. A transaction control method, comprising a wrapper, wherein the resource adapter uses the resource manager wrapper instead of the resource adapter, and the resource manager wrapper does nothing in a prepare process and a commit process. In a distributed transaction processing system in which multiple resource adapters without non-volatile storage share a single resource manager,
By wrapping a resource adapter with a resource adapter wrapper and referencing information representing a group of resource adapters that share a single resource manager, when registering the resource adapter with the transaction manager, register it as a single transaction branch. Make the transaction manager perform a one-phase commit, distribute the settlement process from the resource adapter wrapper to the resource adapter, and do nothing in the settlement process so that the resource adapter does not call the resource manager's decision process redundantly. A transaction control method comprising wrapping a resource manager in a manager wrapper.

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