Abstract: Improved techniques are disclosed for processing transactions or requests in a data processing system. For example, a method for processing requests in a system including a plurality of nodes includes the following steps. At least two nodes of the plurality of nodes receive a plurality of requests. The two nodes exchange information to determine an order for processing requests. The two nodes process the requests in accordance with the order. The order may include a total order or a partial order.

Abstract: A method for communicating information from a first computing node to at least one of the following: a storage device and a second computing node. The first computing node is monitored to collect at least one estimate of available resources, and based on this estimate, an amount of data collected is modified. Then, the modified data is sent to at least one of the following: the storage device and the second computing node. This invention also provides for the determination of an optimum batch size for aggregating data wherein, for a number of batch sizes, costs are estimated for sending batched information to persistent storage and for losing batched data. Then, the optimum batch size is selected from the number of different batch sizes based on sums of these costs. This invention also provides for selective compression of data, wherein it is determined which of a number of compression algorithms do not incur an overhead that exceeds available resources.

Abstract: A system and method for maintaining consistency in a system where multiple copies of an object may exist is provided for maintaining consistent copies. Consistency is maintained using a plurality of consistency policies in which at least one consistency policy results in different performance than a second consistency policy. A consistency policy is selected from the plurality consistency policies for each object to improve system performance.

Abstract: Improved key management techniques are disclosed for temporal access control of one or more services in a computer network. For example, a method for providing access control in a client-server system includes the following steps. A client obtains an authorization key for a time interval. A server derives an encryption key corresponding to a given time and uses the encryption key to encrypt a message. The client derives a decryption key corresponding to the given time and decrypts the message.

Abstract: Improved access control techniques for use in a service-oriented computing environment are disclosed. For example, one method for authenticating a client in a service-oriented environment, wherein the service-oriented environment includes a plurality of services, includes the following steps. At least one service of the plurality of services is invoked. State information is associated with the at least one service invoked. The state information is used to authenticate a client with at least one service. Further, a method for access control in a service-oriented environment, wherein the service-oriented environment includes a plurality of services, includes the following steps. A rule specification language is provided. At least one rule is specified using the rule specification language. A verification is performed to determine whether or not the client satisfies the at least one rule. The client is granted access to a service when the client satisfies the at least one rule.

Abstract: Improved load balancing techniques are disclosed. For example, in one illustrative aspect of the invention, a method of satisfying requests in a system comprised of a plurality of servers comprises the following steps. At least one load balancer is provided for routing requests to the plurality of servers. At the at least one load balancer, a request sent from a client is obtained. At the at least one load balancer, the request is examined. Costs of satisfying the request by at least two of the plurality of servers are estimated. The estimation is based on at least one of a number and a cost of at least one remote access for satisfying the request. The request is routed to a server of the plurality of servers with a low estimated cost of satisfying the request.

Abstract: Techniques are disclosed for automatically determining one or more configuration parameters associated with one or more programs executable by a computing system. For example, in a system including at least one application and at least one parameter which affects a behavior of the at least one application, a method for determining a frequency for invoking the at least one application includes the following steps. The method estimates a cost which includes overhead resulting from invoking the at least one application. The method estimates an improvement in the behavior resulting from modifying the at least one parameter based on invoking the at least one application. The method selects the frequency based on the cost and the improvement.

Abstract: Techniques for efficiently authenticating multiple objects and clustering objects based on access patterns are provided. For example, in an illustrative aspect of the invention, a technique for generating and/or reading authentication information, wherein the authentication information provides evidence that a plurality of objects were one of generated and sent by an entity, comprises using one or more object access patterns indicative of whether at least two of the plurality of objects are accessed within a similar time period to group objects together to reduce an overhead for at least one of generating and reading the authentication information.

Abstract: The illustrative embodiments described herein provide a computer-implemented method, apparatus, and computer program product for deploying a set of virtual software resource templates to a plurality of nodes. The process identifies a set of virtual machine images and metadata to form a set of virtual software resource templates. The process creates a model that indicates a performance metric based on a number of nodes on which a number of virtual machine images is deployed. The process receives a quality of service requirement. The process determines, using the model, a sufficient number of virtual software resource templates in the set of virtual software resource templates and a sufficient number of nodes in the plurality of nodes to fulfill the quality of service requirement. The process deploys the sufficient number of virtual software resource templates on the sufficient number of nodes using the metadata.

Abstract: A system and method for maintaining consistency in a system where multiple copies of an object may exist is provided for maintaining consistent copies. Consistency is maintained using a plurality of consistency policies in which at least one consistency policy results in different performance than a second consistency policy. A consistency policy is selected from the plurality consistency policies for each object to improve system performance.

Abstract: In a client-server environment having a server group including one or more participating servers and one or more controller servers, where each participating server can communicate with at least one controller server, a method for coordinating actions among the servers in the server group comprising the steps of: (1) communicating between a client and at least one of the servers in the server group using a protocol that has limited or no defined procedures for passing state information between the client and the servers; (2) transmitting a request for an action from the client to one of the servers; and (3) communicating among a plurality of servers with at least one controller server coordinating actions of at least some of the servers in response to the request.

Abstract: In a system having a plurality of caches, a method for maintaining cached objects includes storing an object in a plurality of caches. In response to a request to update the object, a future invalidation time is determined when the object should be invalidated in caches currently storing the object. Updating of the object is delayed until the invalidation time has passed.

Abstract: Methods for serving data include maintaining an incomplete version of an object at a server and at least one fragment at the server. In response to a request for the object from a client, the incomplete version of the object, an identifier for a fragment comprising a portion of the object, and a position for the fragment within the object are sent to the client. After receiving the incomplete version of the object, the identifier, and the position, the client requests the fragment from the server using the identifier. The object is constructed by including the fragment in the incomplete version of the object in a location specified by the position.

Abstract: Techniques for improved cache management are provided. In particular, the invention provides techniques for improving the task of updating a cache by efficiently and intelligently combining and controlling cache update operations. For example, a technique may comprise the following steps. A set of keys is determined such that at least one key in the set corresponds to an object in an unknown state. Requests to keys in the set are suspended while the cache is being updated. That is, the set of keys is set to an offline status, i.e., not accepting any request for a key in the set. Then, the set is placed back to an online status, i.e., accepting requests for a key in the set, after the update to the cache is complete.

Abstract: Techniques for managing data objects in conjunction with a computer system are provided. In a technique for clustering data objects on a disk storage device, the invention comprises maintaining a log of at least a portion of accesses (e.g., read and for write operations) to the data objects; determining from the maintained log a cluster comprised of data objects accessed at substantially similar times; and storing the data objects comprising the cluster in close proximity to one another on the disk storage device. In a technique for prefetching data objects on a disk storage device, the invention comprises receiving a request for a data object in a cluster, determining from the log a probability that at least one other data object in the cluster may be subsequently requested; and, in response to the probability being not less than a predetermined value, retrieving both the requested data object and the at least one other data object.

Abstract: Techniques for improved cache management including cache replacement are provided. In one aspect, a distributed caching technique of the invention comprises the use of a central cache and one or more local caches. The central cache communicates with the one or more local caches and coordinates updates to the local caches, including cache replacement. The invention also provides techniques for adaptively determining holding times associated with data storage applications such as those involving caches.

Abstract: A log of transactions is maintained on a persistent storage device. When a block of storage is allocated or deallocated, this transaction is recorded. If the persistent storage device is allowed to be slightly obsolete (i.e., not fully up-to-date), the log stored on the persistent storage device does not necessarily have to be updated right away. By delaying log updating until a certain number of transactions have transpired, memory seeks can be reduced, significantly improving performance. Further, directory information on the persistent storage device may be periodically updated from the log. This is preferably done infrequently enough so that the amortized cost for updating directory information is low.

Abstract: Techniques for automatically detecting similar subsets (e.g., fragments) in electronic documents such as dynamic content-based data, e.g., web pages. The techniques of the invention may perform a systematic analysis of the web pages with respect to one or more of their information sharing behavior, their personalization characteristics, and their change pattern over time. Thus, the invention may be applied to discover fragments in web pages of web sites that are most beneficial for caching the contents of the web site. The present invention also comprises techniques for publishing electronic documents with automatic fragment detection.

Abstract: In a client-server environment having a server group including one or more participating servers and one or more controller servers, where each participating server can communicate with at least one controller server, a method for coordinating actions among the servers in the server group comprising the steps of: (1) communicating between a client and at least one of the servers in the server group using a protocol that has limited or no defined procedures for passing state information between the client and the servers; (2) transmitting a request for an action from the client to one of the servers; and (3) communicating among a plurality of servers with at least one controller server coordinating actions of at least some of the servers in response to the request.

Abstract: Techniques for improved cache management are provided. In particular, the invention provides techniques for improving the task of updating a cache by efficiently and intelligently combining and controlling cache update operations. For example, a technique may comprise the following steps. A set of keys is determined such that at least one key in the set corresponds to an object in an unknown state. Requests to keys in the set are suspended while the cache is being updated. That is, the set of keys is set to an offline status, i.e., not accepting any request for a key in the set. Then, the set is placed back to an online status, i.e., accepting requests for a key in the set, after the update to the cache is complete.