網頁應用程式進行資料庫更版之服務不中斷設計與實作

Abstract

隨著科技的快速發展，網際網路已成為提供商業服務的主要平台。基於網頁之網際網路應用程式是遵循多層級架構而設計，是一個廣被採納用來提供網際網路服務的模型。網頁應用程式會因為軟體錯誤修補、硬體故障或者計劃性的服務更新而發生中斷。網際網路服務一旦遭遇中斷會造成服務供應商龐大的金錢損失，因此，服務不中斷（Service Continuity）是極其重要的，也是目前網頁應用程式最大的挑戰之一。雖然目前有許多的服務不中斷技術已經被發展出來。然而，其中有許多技術只著重在處理單一層級所發生的中斷問題，而不能保證end-to-end的服務不中斷。在此篇論文，我們提出一個機制，用來解決資料庫更版所造成的長時間中斷，同時一併處理因資料庫更版而更換軟體元件時所造成的中斷，以確保end-to-end服務能持續運作。我們並描述如何在實際架構上進行機制的設計以及實作內容。跟現有的方法比較之下，此篇論文提出的方法更有效率且具有最小的額外負擔等優點。

Today, Internet services are utilized as major service platforms to provide business services. The Web-based Internet applications that follow the multi-tier architecture is a well-accepted computation model to provide Internet services. Such model suffers from interruption caused by software failure, hardware error or system upgrade of servers. The interruption may incur money loss to Internet service providers. Thus, Service Continuity is one of the main challenges for the Web-based Internet applications. Although several service continuity technologies have been developed, many of them focus on a single tier of the applications and do not guarantee the end-to-end service continuity. In this paper, we describe the design and implementation for service continuity technology to solve the long time interruption caused by database evolution also deal with the software components upgrade in order to achieve end-to-end service continuity. Comparing with existing approaches, our approach is more efficient and has least overhead.