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Middle-tier database caching for e-business
- International Conference on Very Large Data Bases
"... Scaling up to the enormous and growing Internet population with unpredictable usage patterns, E-commerce applications face severe challenges in cost and manageability, especially for database servers that are deployed as those applications ’ back-ends in a multi-tier configuration. Middle-tier datab ..."
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Cited by 85 (4 self)
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Scaling up to the enormous and growing Internet population with unpredictable usage patterns, E-commerce applications face severe challenges in cost and manageability, especially for database servers that are deployed as those applications ’ back-ends in a multi-tier configuration. Middle-tier database caching is one solution to this problem. In this paper, we present a simple extension to the existing federated features in DB2 UDB, which enables a "regular " DB2 instance to become a DBCache without any application modification. On deployment of a DBCache at an application server, arbitrary SQL statements generated from the unchanged application hitherto intended for a back-end database server, can be answered: at the cache, at the back-end database server, or at both locations in a distributed manner. The factors that determine the distribution of workload include the SQL statement type, the cache content, the application requirement on data freshness, and cost-based optimization at the cache. We have developed a research prototype of DBCache, and conducted an extensive set of experiments with an E-Commerce benchmark to show the benefits of this approach and illustrate tradeoffs in caching considerations. 1
Form-Based Proxy Caching for Database-Backed Web Sites: Keywords and Functions
, 2008
"... Web caching proxy servers are essential for improving web performance and scalability, and recent research has focused on making proxy caching work for database-backed web sites. In this paper, we explore a new proxy caching framework that exploits the query semantics of HTML forms. We identify two ..."
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Cited by 58 (3 self)
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Web caching proxy servers are essential for improving web performance and scalability, and recent research has focused on making proxy caching work for database-backed web sites. In this paper, we explore a new proxy caching framework that exploits the query semantics of HTML forms. We identify two common classes of form-based queries from real-world database-backed web sites, namely, keyword-based queries and function-embedded queries. Using typical examples of these queries, we study two representative caching schemes within our framework: (i) traditional passive query caching, and (ii) active query caching, in which the proxy cache can service a request by evaluating a query over the contents of the cache. Results from our experimental implementation show that our form-based proxy is a general and flexible approach that efficiently enables active caching schemes for database-backed web sites. Furthermore, handling query containment at the proxy yields significant performance advantages over passive query caching, but extending the power of the active cache to do full semantic caching appears to be less generally effective.
Optimization of Run-time Management of Data Intensive Web Sites
- In Proc. of VLDB
, 1999
"... An increasing number of web sites have their data extracted from relational databases. Several commercial products and research prototypes have been moving in the direction of declarative specification of the sites' structure and content. Specifically, the entire site is specified using a colle ..."
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Cited by 29 (2 self)
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An increasing number of web sites have their data extracted from relational databases. Several commercial products and research prototypes have been moving in the direction of declarative specification of the sites' structure and content. Specifically, the entire site is specified using a collection of queries describing the site's nodes (corresponding to web pages and the data contained in them) and edges (corresponding to the hyperlinks). Given this paradigm, an important issue is when to compute the site's pages. Two extreme approaches, with obvious drawbacks, are (1) to precompute the entire site in advance, and (2) to evaluate on demand all the queries necessary to construct a given page. We consider the problem of automatically optimizing the run-time management of declaratively specified web sites. In our approach, given a declarative site specification and constraints on the application, an efficient run-time evaluation policy is automatically derived. An evaluation policy spec...
Active query caching for database web servers
- WebDB
, 2000
"... Abstract. A substantial portion of web traffic consists of queries to database web servers. Unfortunately, a common technique to improve web scalability, proxy caching, is ineffective for database web servers because existing web proxy servers cannot cache queries. To address this problem, we modify ..."
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Cited by 27 (2 self)
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Abstract. A substantial portion of web traffic consists of queries to database web servers. Unfortunately, a common technique to improve web scalability, proxy caching, is ineffective for database web servers because existing web proxy servers cannot cache queries. To address this problem, we modify a recently proposed enhanced proxy server, called an active proxy, to enable Active Query Caching. Our approach works by having the server send the proxy a query applet, which can process simple queries at the proxy. This enables the proxy server to share the database server workload as well as to reduce the network traffic. We show both opportunities and limitations of this approach through a performance study. Keywords:Active query caching, proxy caching, database web servers, query containment. 1
The NODS project: Networked Open Database Services
- In Proc. of the 14th European Conference on Object-Oriented Programming (ECOOP 2000)- Symposium on Objects and Databases
, 2000
"... This paper introduces the NODS project been currently conducted at the LSR-IMAG laboratory, Grenoble { France. NODS aims at dening an open, adaptable, evolutionary architecture that can be extended and customized on a per-application basis. A database system is seen as an infrastructure comprise ..."
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Cited by 18 (6 self)
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This paper introduces the NODS project been currently conducted at the LSR-IMAG laboratory, Grenoble { France. NODS aims at dening an open, adaptable, evolutionary architecture that can be extended and customized on a per-application basis. A database system is seen as an infrastructure comprised of co-operating adaptable and extensible services from which applications can build their customized NODS database components. Furthermore, services or database systems conguration can be adapted at runtime (e.g., add new services, change services internal policies), according to environmental changes. 1
A Last-Resort Semantic Cache for Web Queries
"... Abstract. We propose a method to evaluate queries using a last-resort semantic cache in a distributed Web search engine. The cache stores a group of frequent queries and for each of these queries it keeps minimal data, that is, the list of machines that produced their answers. The method for evaluat ..."
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Cited by 4 (2 self)
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Abstract. We propose a method to evaluate queries using a last-resort semantic cache in a distributed Web search engine. The cache stores a group of frequent queries and for each of these queries it keeps minimal data, that is, the list of machines that produced their answers. The method for evaluating the queries uses the inverse frequency of the terms in the queries stored in the cache (Idf) to determine when the results recovered from the cache are a good approximation to the exact answer set. Experiments show that the method is effective and efficient. 1
Template-based proxy caching for tablevalued functions
- Proc. Ninth Int’l Conf. Database Systems for Advanced Applications (DASFAA ’04
, 2004
"... Abstract. Certain types of database-backed web sites heavily utilize userdefined functions in SQL queries. Unfortunately, existing web proxy caching schemes can not handle these functions. In order to enable proxy caching for such web sites, we propose a template-based proxy caching framework, a fun ..."
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Cited by 3 (1 self)
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Abstract. Certain types of database-backed web sites heavily utilize userdefined functions in SQL queries. Unfortunately, existing web proxy caching schemes can not handle these functions. In order to enable proxy caching for such web sites, we propose a template-based proxy caching framework, a function proxy, for table-valued functions. In our framework, function templates are registered with the proxy so that the proxy can answer new queries based on previously cached data in collaboration with the original web site. We identify a common class of function-embedded queries and present several active caching schemes for them. Our experiments with real web sites show the feasibility and usefulness of the function proxy. Additionally, we find that cache-intersecting queries may not be worth handling at the proxy and that containment-based active caching is efficient and practical. 1
ABSTRACT Building adaptable cache services
"... Caching is crucial to improve performances in many computing systems. It is context dependent, thus many types of cache exist. As a consequence, when a cache is required, it is usually built from scratch. Such a solution is time (and money) consuming, in particular in data grid context where several ..."
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Cited by 3 (3 self)
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Caching is crucial to improve performances in many computing systems. It is context dependent, thus many types of cache exist. As a consequence, when a cache is required, it is usually built from scratch. Such a solution is time (and money) consuming, in particular in data grid context where several caches may be required. This paper proposes ACS (Adaptable Cache Service), a framework which allows building adaptable cache services. It presents a generic cache definition and provides a description of models implemented in the framework. ACS aims at facilitating the development of cache services for any application. Our current experiences concern their use in building a data grid middleware (Gedeon project).
A Semantic Caching Method Based on Linear Constraints
- In Proc. of International Symposium on Database Applications in Non-Traditional Environments (DANTE’99
, 1999
"... Because performance is a crucial issue in database systems, data caching techniques have been studied in database research field, especially in client-server databases and distributed databases. Recently, the idea of semantic caching has been proposed. The approach uses semantic information to desc ..."
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Cited by 2 (0 self)
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Because performance is a crucial issue in database systems, data caching techniques have been studied in database research field, especially in client-server databases and distributed databases. Recently, the idea of semantic caching has been proposed. The approach uses semantic information to describe cached data items so that it tries to exploit not only temporal locality but also semantic locality to improve query response time. In this paper, we propose linear constraint-based semantic caching as a new approach to semantic caching. Based on the idea of constraint databases, we describe the semantic information about the cached relational tuples as compact constraint tuples. The main focus in this paper is the representation method of cache information and the cache examination algorithm. 1. Introduction Data caching has been investigated in various fields of database research such as client-server databases [5, 18], data warehouses [6], and distributed and heterogeneous database...
Site-Autonomous Distributed Semantic Caching
"... Semantic caching augments cached data with a semantic description of the data. These semantic descriptions can be used to improve execution time for similar queries by retrieving some data from cache and issuing a remainder query for the rest. This is an improvement over traditional page caching, si ..."
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Cited by 1 (1 self)
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Semantic caching augments cached data with a semantic description of the data. These semantic descriptions can be used to improve execution time for similar queries by retrieving some data from cache and issuing a remainder query for the rest. This is an improvement over traditional page caching, since caches are no longer limited to only base tables but are extended to contain intermediate results. In large-scale distributed database systems, using a central server with complete knowledge of the system will be a serious bottleneck and single point of failure. In this paper, we propose a distributed semantic caching method where sites make autonomous caching decisions based on locally available information, thereby reducing the need for centralized control. We implement the method in the DASCOSA-DB distributed database system prototype and use this implementation to do experiments that show the applicability and efficiency of our approach. Our evaluation shows that execution times for queries with similar subqueries are significantly reduced and that overhead caused by cache management is marginal.
