物件導向資料庫系統中索引技巧及緩衝區管理之整合研究

Abstract

緩衝區管理及輔助存取機制是改善資料庫系統效能的兩種重要技巧。在這 篇論文中，我們探討在物件導向資料庫中多數可應用的輔助存取機制及研 究它們在緩衝區管理下的影響。我們提出一成本模型來描述整合這兩種技 巧的影響，針對各種輔助存取機制下所執行之不同查詢型態，此成本模型 被用來推導磁碟存取的成本公式。藉由此成本公式，我們比較這些機制的 效能，並指出對應各種機制其適當取代及配置策略。我們也分析了這兩種 技巧之整合對系統效能的影響。由於同時考慮這兩因素，本論文所推導出 之的成本模型更實用於真正的資料庫系統。

Buffer management and auxiliary access mechanisms are two important techniques to improve database system performance. In this thesis, we analytically investigate most available auxiliary access mechanisms in OODBMS and study their impact on buffer management. We present a cost model to describe the integrated effect of both techniques. The model is used to derive the cost formulae of disk access for various auxiliary access mechanisms when evaluating different types of queries. By the cost formulae, we compare the performance of these mechanisms and indicate the adequate replacement policies and allocation policies associated with each particular mechanism. We also analyze the performance impact due to the integration of both techniques. The derived cost model is more applicable to real database systems since the two performance factors are considered.