International Business Machines Corporation

Globalfoundries Inc.

Avraham Harpaz

Nir Naaman

Yoav Tock

Idan Zach

Gidon Gershinsky

Chen Chen

Benjamin Mandler

Eliezer Dekel

Alexander Krits

Cornell G Wright, Jr

Doron Cohen

Simona Cohen

Konstantin Shagin

Alan Hartman

Mila Keren

Foluso Olaiya Okunseinde

Harel Paz

Mel Shalev

Cornell Wright

An example system includes a processor to receive updates for a database of a publish and subscribe system. The processor is to generate an optimistic update based on the received updates. The processor is also to adaptively update the database using the optimistic update. In some examples, the processor generates a bulk optimistic update based on the optimistic update and adaptively updates the database using the bulk optimistic update or a read-modify-write sequence.

Adaptively updating databases of publish and subscribe systems using optimistic updates

Examples of techniques for tracking client sessions in a publish and subscribe system using a shared repository are described herein. An example system includes a processor of a server to receive a connection request with a client identifier from a client a predefined policy for duplicate client sessions. The processor is to query a shared repository of the system using the client identifier. The processor is to also execute a set of actions based on the predefined policy, a query result including a detected duplicate client session from the shared repository, and a set of parameters.

Tracking client sessions in publish and subscribe systems using a shared repository

Migration of a durable client in a publish/subscribe system from a first server of a cluster to a second server of the cluster. The method comprises the second server receiving subscription information of the durable client; the second server establishing a message queue for the durable client; the second server sending a switch command to all active servers of the cluster; in response to the second server obtaining, from an active server, an acknowledgement of the switch command, the second server inserting a marker to the message queue indicating switching point of the active server; and in response to the second server obtaining, from the first server, a message indicating the first server flushed all messages prior to respective switching points for all active servers, connecting the durable client to the second server and transmitting messages thereto by the second server. As a result, the durable client is migrated from the first server to the second server without disrupting data traffic to uninvolved clients.

Migration of durable clients in a clustered publish/subscribe system

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.

Efficient lookup in multiple bloom filters

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.

Efficient size reduction of a bloom filter

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 subscription group.

Cluster assisted MQTT client coverage for fat-pipe cloud applications

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 the selected messaging engine(s) to the subscription group(s).

MQTT cluster shared subscription hub for fat-pipe cloud applications

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.

Distributing retained messages information in a clustered publish/subscribe system

A method comprising using at least one hardware processor for managing persistent messaging data in a volatile memory, writing the persistent messaging data to a first section of a Fast Persistent Memory (FPM), responsive to the first section of the FPM approaching a full state, offloading the persistent messaging data from the first section of the FPM to a hard disk device (HDD), and erasing the persistent messaging data from the first section of the FPM, recording, in a second section of the FPM, an identifier of said offloading, responsive to receiving a request to erase or modify at least some of the persistent messaging data in the HDD, updating the identifier of the offloading in the second section of the FPM while leaving the persistent messaging data in the HDD intact, and responsive to a server failure, selectively reading at least some of the persistent messaging data from the HDD to the volatile memory, wherein the selective reading is based on the identifier of the offloading in the second section of the FPM.

Persistent messaging mechanism

A method comprising managing persistent messaging data in a volatile memory of a primary instance of a multi-node server, wherein the persistent messaging data is stored in a Hard Disk Device (HDD) and a Fast Persistent Memory (FPM) of the primary instance, repeatedly replicating the persistent messaging data to a corresponding HDD and a corresponding FPM of at least one standby instance of the multi-node server, repeatedly copying the persistent messaging data stored in the FPM or the HDD of the at least one standby instance to a Recovery Memory Region (RMR) in a volatile memory of the at least one standby instance, and responsive to a failure of the primary instance, initiating a failover procedure by the standby instance, wherein the failover procedure comprises reading at least some of the persistent messaging data from the RMR in lieu of the HDD of the at least one standby instance.

A computer-implemented method, a computerized system and a product for providing a cluster of replicated servers. The method performed by a computerized server in a cluster of servers, wherein the cluster of servers are executing replicated instances of an application, wherein the replicated instances are configured to perform the same processing of the same input, comprising: detecting a message loss in the server; electively determining a responsive action to the message loss; and notifying the cluster of servers of the responsive action determined by the server, whereby other servers of the cluster of servers are able to mimic operation of the server by simulating the responsive action.

Selective message loss handling in a cluster of replicated servers

Systems and methods for optimal data storage are provided. The method comprises storing data objects that are most closely related in a storage container by modeling a constraint satisfaction problem for placement of said data objects in one or more storage containers, wherein a weight is assigned to an edge connecting two data objects based on an association defining relationships between the two data objects connected by said edge, taking into account certain penalties for placing multiple copies of the same object in the one or more storage containers, and wherein a storage container comprises a logical or physical storage area as a unit of storage.

Self-contained placement of data objects in a data storage system

A method for server replication in a network environment is provided. The primary server provides a first service to a client. If the first service involves interaction with a non-deterministic data source, the primary server performs the interaction and provides information about the interaction to a secondary server that is a replica of the primary server. The secondary server uses the information about the interaction to synchronize the secondary server with the primary server.

Replication in a network environment

A group communication service maintains synchronization limiting the group to the processing entities that receive a plurality of source message streams from sources outside the group and transmit delivery message streams to destinations that are outside the group. Synchronization of message ordering and other state synchronization directives are communicated from a leader exclusively to other group members. Once having declared themselves to be synchronized and active by a reply protocol message, which is an opaque object and is interpreted by an application layer, the processing entities independently process the source message streams in accordance with the order specified in the directives, without requiring additional sequencing information from another processing entity.

Group communication system achieving efficient total order and state synchronization in a multi-tier environment

A method, system and computer program product for transmitting data entities, the method includes: receiving data entities to be transmitted over multiple channels; and preventing a transmission of data entities that are to be transmitted over congested channels while transmitting data entities that are to be are to be transmitted over non-congested channels.

Growing community of inventors

Haifa, Israel

Avraham Harpaz