US 7,849,464 B2Granted

Protection against interleaving transactions using a transaction manager

AssigneeOracle International Corporation

InventorAlexander J. Somogyi

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Abstract

A transaction manager maintains an enlistment data structure used for managing resource object enlistment. A transaction manager may receive an enlistment request initiated from a resource object. Upon receiving the request, the transaction manager will determine if the resource object is already enlisted. If the resource object is already enlisted, the transaction manager will block the enlistment request. If the resource object is not enlisted, the transaction manager will enlist the resource. Upon enlistment, the resource object will perform a requested task or service. After the requested task or service is complete, the resource initiates a delistment request to the transaction manager. After receiving the delistment request from the resource, object, the transaction manager is delisted from the enlistment data structure.

Claims17

Dependent claims

A system for supporting resource enlistment synchronization, comprising:

an application server with a plurality of threads, wherein the application server runs on one or more processors and is associated with a plurality of applications, wherein each application is associated with at least one said thread;
at least one resource object, wherein the at least one resource object is associated with a resource connection object;
a transaction manager that manages a plurality of transactions, wherein each transaction is associated with each application;
wherein the resource connection object operates to perform:
receiving a request, to access the at least one resource object that is associated with the resource connection object, from an application of the plurality of applications that runs on a thread of the plurality of threads, and
placing a call to the transaction manager and informing the transaction manager that current work performed by the at least one resource object is to be associated with a current transaction that is associated with the application, and
wherein, after receiving the call from the resource connection object, the transaction manager operates to perform:
first checking to see if there is an in-progress enlistment of the at least one resource object by another thread in another transaction,
if there is a lock,
blocking the request to enlist the resource object in the transaction and preventing different transactions from enlisting a logical connection to the at least one resource object at same time, and
initiating the at least one resource object to perform work associated with the thread and the current transaction, after the at least one resource object is delisted from another transaction that owns the lock,
if there is no lock,
enlisting the at least one resource object in the transaction and signaling the at least one resource object to begin processing the request,
receiving from the at least one resource object a delist resource method call, after a result is obtained for the request, to delist the at least one resource object from the current transaction and provides the result to the application, and
initiating the at least one resource object to perform work associated with another thread and another transaction.

12 more elements

A method for supporting resource enlistment synchronization, comprising:

associating a plurality of applications with an application server with a plurality of threads, wherein the application server runs on one or more processors, and wherein each application is associated with at least one said thread;
providing at least one resource object, wherein the at least one resource object is associated with a resource connection object;
providing a transaction manager that manages a plurality of transactions, wherein each transaction is associated with each application;
allowing the resource connection object to perform:
receiving a request, to access the at least one resource object that is associated with the resource connection object, from an application of the plurality of applications that runs on a thread of the plurality of threads, and
placing a call to the transaction manager and informing the transaction manager that current work performed by the at least one resource object is to be associated with a current transaction that is associated with the application;
and
after receiving the call from the resource connection object, allowing the transaction manager to perform:
first checking to see if there is an in-progress enlistment of the at least one resource object by another thread in another transaction,
if there is a lock,
blocking the request to enlist the resource object in the transaction and preventing different transactions from enlisting a logical connection to the at least one resource object at same time, and
initiating the at least one resource object to perform work associated with the thread and the current transaction, after the at least one resource object is delisted from another transaction that owns the lock,
if there is no lock,
enlisting the at least one resource object in the transaction and signaling the at least one resource object to begin processing the request,
receiving from the at least one resource object a delist resource method call, after a result is obtained for the request, to delist the at least one resource object from the current transaction and provides the result to the application, and
initiating the at least one resource object to perform work associated with another thread and another transaction.

13 more elements

A computer-readable storage medium, storing instructions for supporting resource enlistment synchronization, the instructions comprising the steps of:

associating a plurality of applications with an application server with a plurality of threads, wherein the application server runs on one or more processors, and wherein each application is associated with at least one said thread;
providing at least one resource object, wherein the at least one resource object is associated with a resource connection object;
providing a transaction manager that manages a plurality of transactions, wherein each transaction is associated with each application;
allowing the resource connection object to perform:
receiving a request, to access the at least one resource object that is associated with the resource connection object, from an application of the plurality of applications that runs on a thread of the plurality of threads, and
placing a call to the transaction manager and informing the transaction manager that current work performed by the at least one resource object is to be associated with a current transaction that is associated with the application;
and
after receiving the call from the resource connection object, allowing the transaction manager to perform:
first checking to see if there is an in-progress enlistment of the at least one resource object by another thread in another transaction,
if there is a lock,
blocking the request to enlist the resource object in the transaction and preventing different transactions from enlisting a logical connection to the at least one resource object at same time, and
initiating the at least one resource object to perform work associated with the thread and the current transaction, after the at least one resource object is delisted from another transaction that owns the lock,
if there is no lock,
enlisting the at least one resource object in the transaction and signaling the at least one resource object to begin processing the request,
receiving from the at least one resource object a delist resource method call, after a result is obtained for the request, to delist the at least one resource object from the current transaction and provides the result to the application, and
initiating the at least one resource object to perform work associated with another thread and another transaction.

13 more elements

Dependencies are inferred from the claim text.