The Research Of Transaction Concurrency Control In Web Service Environment

Transaction Technology is used to guarantee the execution of concurrent transactionsefficiently and correctly. Web Service technology integrates data and function of differentapplications on the Internet without any special software or hardware from third party.Web application’s characteristics of loosely-coupled, distribution and autonomydetermines the feature of its transaction needs not follow conventional strict ACID(Atomicity, Consistency, Isolation and Durability) and setting up relax ACID rules basedon semantic of application is required. Using transaction technology to study theconcurrency control mechanism suitable for the characteristics of Web applications is onehot topic in current research.For the applications in which one kind of resource scattered in different serversdistributed in diverse areas, we define relaxed ACID rules that guarantee applicationsemantic correct. We design and implement a concurrent transaction control system namedas LA-Transaction to ensure the efficiency for concurrent applications. We propose aconcept of resource alternative set. One resource object is regarded as a collection ofmultiple equivalent resources and the necessary and sufficient condition of the access tothe resource lock is that one of the resources is locked. Therefore, it refines lockgranularity of resources to improve the performance of concurrency. LA-Transaction usesbuffer pool technology to maintain a transaction request pool which is able to receive afew transaction requests in the same time for each available resource and integratesavailable resource information of transaction participants to select fastest transaction toraise response speed. Via dynamically resizing the transaction request, it avoids thestarvation of some transaction requests.We take the applications of National Laboratory Animal Administrative ServicePlatform as test cases for LA-Transaction and existing WS-Transaction. From the resultsof our test and analysis, LA-Transaction is able to guarantee correct execution ofconcurrent transactions. Compared with WS-Transaction under the same conditions,LA-Transaction increases nearly30%for throughput rate, reduces21%for longestresponse time and22%for average response time.