Abstract: A computer implemented method of improving server coverage of a publish-subscribe cluster comprising using one or more hardware processors to execute one or more shared subscriptions hubs each adapted to retrieve shared subscriptions information from a cluster comprising multiple servers executing multiple messaging engines of a publish-subscribe service for forwarding messages to a plurality of subscribing clients, each message is associated with one or more of a plurality of topics, receive shared subscriptions requests for subscribing for one or more of the topics from distributed subscriptions client(s) applying shared subscriptions for the topic(s) through subscription group(s) comprising a subset of the subscribing clients, connect to preferred messaging engine(s) selected to improve server coverage of the subscription group(s) according to the shared subscriptions information to serve each of the plurality of shared subscriptions requests and forward messages associated with the topic(s) received from

Abstract: Embodiments of the present systems and methods may provide the capability to monitor and detect failure of nodes in a data center environment by using a software defined failure detector that can be adjusted to varying conditions and data center topology. In an embodiment, a computer-implemented method for monitoring and detecting failure of electronic systems may comprise, in a system comprising a plurality of networked computer systems, defining at least one failure detection agent to monitor operation of other failure detection agents running on at least some of the electronic systems, and defining, at the controller, and transmitting, from the controller, topology information defining a topology of the failure detection agents to the failure detection agents, wherein the topology information includes information defining which failure detection agents each failure detection agent is to monitor.

Abstract: When a request is received to perform a data operation requiring an interaction with any one of multiple data replicas stored on one or more data storage devices and managed by a quorum-based data management protocol in which completion of a data update is reported to an initiator of the data update when acceptance of the data update is reported by a majority of the data replicas, the data operation is routed to be performed using one of a predefined minority of the data replicas if the data operation requires less than strong consistency, is a read-only data operation, and meets a predefined criterion of being computationally time-intensive or computationally resource-intensive, or routed to be performed using a predefined majority of the data replicas if the data operation requires strong consistency or requires a data write operation or does not meet the predefined criterion.

Abstract: A computer implemented method of improving server coverage of a publish-subscribe cluster comprising using one or more hardware processors to execute one or more shared subscriptions hubs each adapted to retrieve shared subscriptions information from a cluster comprising multiple servers executing multiple messaging engines of a publish-subscribe service for forwarding messages to a plurality of subscribing clients, each message is associated with one or more of a plurality of topics, receive shared subscriptions requests for subscribing for one or more of the topics from distributed subscriptions client(s) applying shared subscriptions for the topic(s) through subscription group(s) comprising a subset of the subscribing clients, connect to preferred messaging engine(s) selected to improve server coverage of the subscription group(s) according to the shared subscriptions information to serve each of the plurality of shared subscriptions requests and forward messages associated with the topic(s) received from

Abstract: A computer implemented method of improving server coverage of a publish-subscribe cluster of servers, comprising using a cluster comprising a plurality of servers each having hardware processor(s), the cluster is adapted to execute messaging engines of a publish-subscribe service for forwarding a plurality of messages to a plurality of subscribing clients, each message is associated with one of a plurality of topics, wherein distributed subscriptions client(s) applies shared subscriptions for one or more topics through subscription group(s) each comprising a subset of the subscribing clients, monitor shared subscriptions made by the subscription group(s) to each of the messaging engines for each topic, generate a shared subscriptions information for each topic by analyzing the shared subscriptions and publish the shared subscriptions information to the clients to allow client(s) of the subscription group(s) to subscribe for the topic(s) on a preferred messaging engine to improve a server coverage of their sub

Abstract: A method, product and apparatus for distributing retained messages information in a clustered publish/subscribe system. The method comprising obtaining a set of Retained Message Filters (RMFs) comprising a RMF for each server in the cluster, wherein the RMF representing a set of topics for which retained messages are retained by the server, the RMF being configured to approximate whether the server retains a retained message that matches a subscription; responsive to receiving a subscription request from a client, applying the set of RMFs to the subscription to obtain an indication of a set of servers that potentially retain retained messages that match the subscription; triggering each server in the set of servers to perform retrieval of retained messages that match the subscription; and sending to the client the retained messages retrieved from the servers in the set of servers.

Abstract: A publish-subscribe data messaging system in which wildcard subscriptions are represented in an approximate membership set or filter, such as a Bloom filter, for distribution to brokers together with formatting rules associated with the wildcard subscriptions, where a broker receiving a publication topic of a data publication for distribution to other brokers uses the formatting rules provided by any given broker to create wildcard versions of the publication topic for matching with the wildcard subscriptions that are represented in the approximate membership sets or filters provided by the given brokers, where, if a match exists, the data publication is forwarded to the given broker.

Abstract: Enhancing performance in a multicasting system. Flow rates in a multicasting system are monitored as system characteristics change. The multicasting system is operated based on a first mapping between data flows and multicasting groups. Data is disseminated by way of the mapping to subscribers to one or more of the data flows. The flow rate thresholds of satisfied flows are decreased to minimize the difference between the flow rate thresholds and respective target transmission rates of the satisfied flows, as the system's feasible data transmission workload is maintained with respect to subscriber reception rate capacities. The flow rate thresholds of unsatisfied flows are increased to minimize the difference between the flow rate threshold and respective target transmission rates for the unsatisfied flows and to limit occurrences of data transmission delays or losses, as the system's feasible data transmission workload is maintained with respect to subscriber reception rate capacities.

Abstract: A computerized method for dynamic consistency management of server side cache management units in a distributed cache, comprising: updating a server side cache management unit by a client; assigning each of a plurality of server side cache management units to one of a plurality of propagation topology groups according to an analysis of a plurality of cache usage measurements thereof, each of said propagation topology groups is associated with a different write request propagation scheme; and managing client update notifications of members of each of said propagation topology groups according to the respective said different write request propagation scheme which is associated therewith.

Abstract: A hybrid quorum system capable of supporting both persistent and non-persistent operations is disclosed. A computerized system, computerized apparatus, computer program product and method useful for providing a hybrid quorum system are disclosed. A replicated process in a Replicated State Machine (RSM) is configured to receive transient operations and perform such operations without storing the transient operations in a persistent storage of the replicated process. The replicated process is further configured to receive persistent operations and accordingly store such operations in a persistent storage, such as in an operation log, and perform the operations.

Abstract: When a request is received to perform a data operation requiring an interaction with any one of multiple data replicas stored on one or more data storage devices and managed by a quorum-based data management protocol in which completion of a data update is reported to an initiator of the data update when acceptance of the data update is reported by a majority of the data replicas, the data operation is routed to be performed using one of a predefined minority of the data replicas if the data operation requires less than strong consistency, is a read-only data operation, and meets a predefined criterion of being computationally time-intensive or computationally resource-intensive, or routed to be performed using a predefined majority of the data replicas if the data operation requires strong consistency or requires a data write operation or does not meet the predefined criterion.

Abstract: Method, system and product for efficient size reduction of a Bloom filter. The method includes: creating an interleaved Bloom filter based on a Bloom filter, wherein the interleaved Bloom filter is defined so as to have non-sequential cells of the Bloom filter be positioned sequentially, wherein the interleaved Bloom filter interleaves segments of the Bloom filter, wherein a size of the segments is based on an interleaving factor. A reduced size Bloom filter having a number cells below the number of cells of the Bloom filter is computed. The computation includes computing a value of a cell in the reduced size Bloom filter based on two or more values of cells in the interleaved Bloom filter.

Abstract: A method comprising obtaining a Bloom filter array, wherein a size of a first Bloom filter is smaller than a size of a second Bloom filter and modifying at least a portion of the plurality of Bloom filters to create a modified Bloom filter array comprising a modified plurality of Bloom filters each of which having a same size, wherein the same size is greater than the size of the first Bloom filter, wherein said modifying comprises: duplicating the first Bloom filter to create a modified first Bloom filter comprising two or more concatenated copies of the first Bloom filter. The method may also include performing lookup in the Bloom filter array by computing a hash value of a key and accessing a bit in the hash value location in each Bloom filter of the modified Bloom filter array to determine lookup outcome in each Bloom filter.

Abstract: A method, product and apparatus for distributing retained messages information in a clustered publish/subscribe system. The method comprising obtaining a set of Retained Message Filters (RMFs) comprising a RMF for each server in the cluster, wherein the RMF representing a set of topics for which retained messages are retained by the server, the RMF being configured to approximate whether the server retains a retained message that matches a subscription; responsive to receiving a subscription request from a client, applying the set of RMFs to the subscription to obtain an indication of a set of servers that potentially retain retained messages that match the subscription; triggering each server in the set of servers to perform retrieval of retained messages that match the subscription; and sending to the client the retained messages retrieved from the servers in the set of servers.

Abstract: A publish-subscribe data messaging system in which wildcard subscriptions are represented in an approximate membership set or filter, such as a Bloom filter, for distribution to brokers together with formatting rules associated with the wildcard subscriptions, where a broker receiving a publication topic of a data publication for distribution to other brokers uses the formatting rules provided by any given broker to create wildcard versions of the publication topic for matching with the wildcard subscriptions that are represented in the approximate membership sets or filters provided by the given brokers, where, if a match exists, the data publication is forwarded to the given broker.

Abstract: Enhancing performance in a multicasting system. Flow rates in a multicasting system are monitored as system characteristics change. The multicasting system is operated based on a first mapping between data flows and multicasting groups. Data is disseminated by way of the mapping to subscribers to one or more of the data flows. The flow rate thresholds of satisfied flows are decreased to minimize the difference between the flow rate thresholds and respective target transmission rates of the satisfied flows, as the system's feasible data transmission workload is maintained with respect to subscriber reception rate capacities. The flow rate thresholds of unsatisfied flows are increased to minimize the difference between the flow rate threshold and respective target transmission rates for the unsatisfied flows and to limit occurrences of data transmission delays or losses, as the system's feasible data transmission workload is maintained with respect to subscriber reception rate capacities.

Abstract: A computerized method for dynamic consistency management of server side cache management units in a distributed cache, comprising: updating a server side cache management unit by a client; assigning each of a plurality of server side cache management units to one of a plurality of propagation topology groups according to an analysis of a plurality of cache usage measurements thereof, each of said propagation topology groups is associated with a different write request propagation scheme; and managing client update notifications of members of each of said propagation topology groups according to the respective said different write request propagation scheme which is associated therewith.

Abstract: Enhancing performance in a multicasting system comprising monitoring filtering costs in a multicasting system as system characteristics change over time, wherein the multicasting system is operating based on a first mapping, between a plurality of data flows and multicasting groups, to disseminate data to users that subscribe to one or more of the data flows; computing a second mapping in response to determining that overhead associated with filtering of unwanted flows at the user level has exceeded a threshold; and transitioning the multicasting system from using the first mapping to using the second mapping, in response to determining that the second mapping is feasible as applicable to one or more constraints associated with the multicasting system.

Abstract: Systems and methods for data casting in an interest aware peer network are provided. The method comprises determining whether a set of interests associated with a node in a network is updated, wherein the set of interests comprises one or more topics IDs, wherein each topic ID corresponds to a topic of interest associated with said node; distributing the set of interests associated with the node to one or more neighboring nodes by way of a first distribution scheme until N nodes in the network are aware of the updated set of interests for the node; providing each node in the network with a mechanism to determine value of a topic of interest in a set of interests received in association with a node based on a topic ID included in the set of interests for the node.

Abstract: Enhancing performance in a multicasting system comprising monitoring filtering costs in a multicasting system as system characteristics change over time, wherein the multicasting system is operating based on a first mapping, between a plurality of data flows and multicasting groups, to disseminate data to users that subscribe to one or more of the data flows; computing a second mapping in response to determining that overhead associated with filtering of unwanted flows at the user level has exceeded a threshold; and transitioning the multicasting system from using the first mapping to using the second mapping, in response to determining that the second mapping is feasible as applicable to one or more constraints associated with the multicasting system.