Abstract: A node includes storage that stores a portion of high accessibility data corresponding to a shard that is divided into revisions. The portion of the high accessibility data is managed based on an activity state model including a writing state, a resolving state, a metadata update state, and a reading state. The node further includes a repository manager that obtains a cross-shard read request for the high accessibility data; makes a determination that the portion of the high accessibility data is not in the reading state; in response to the determination, adds the cross-shard read request to a delayed action queue at the revision of a last delayed action in the delayed action queue; and after processing the last delayed action in the delayed action queue and while in the resolving state: converts the cross-shard read request to a read request; and processes the read request.

Abstract: Embodiments of the invention relate to a method for managing subscriptions. The method includes initiating execution of a first subscription, in response to the initiating, obtaining a first subscription barrier associated with a first subscription, making, using the first subscription barrier, a first determination to block execution of a first query request associated with the first subscription, and in response to the first determination, ceasing execution of the first subscription.

Abstract: In general, the invention relates to a method for servicing query requests in a distributed system. The method includes generating a data flow graph for a data model using a plurality of metadata documents, where each of the metadata documents is associated with a consistency zone, and servicing a query request using the data flow graph and data associated with the data model.

Abstract: In general, the invention relates to a method for servicing query requests in distributed systems. The method includes making a first determination by a query node that it is associated with a dataspace, making a second determination that data associated with a first input sub-region is not present on the query node, where the first input sub-region is associated with the dataspace. Based on the first determination and the second determination, the method includes obtaining data for the entire dataspace from persistent storage, associating at least a portion of the obtained data with the first input sub-region to obtain a populated first input sub-region, and servicing a query request using the populated first input sub-region.

Abstract: A node includes storage that stores a portion of high accessibility data corresponding to a shard that is divided into revisions. The portion of the high accessibility data is managed based on an activity state model including a writing state, a resolving state, a metadata update state, and a reading state. The node further includes a repository manager that obtains a cross-shard read request for the high accessibility data; makes a determination that the portion of the high accessibility data is not in the reading state; in response to the determination, adds the cross-shard read request to a delayed action queue at the revision of a last delayed action in the delayed action queue; and after processing the last delayed action in the delayed action queue and while in the resolving state: converts the cross-shard read request to a read request; and processes the read request.

Abstract: A node includes storage that stores a portion of high accessibility data that is divided into revisions and managed based on an activity state model. The node also includes a repository manager that keys read requests of the data access requests for the high accessibility data to a revision of the revisions of the portion of the high accessibility data based on an activity state associated with the portion of the high accessibility data when the read requests are obtained to obtain keyed read requests; keys write requests for the high accessibility data to future revisions of the revisions of the high accessibility data when the write requests are obtained to obtain keyed write requests; adds the keyed read requests to a read queue; adds the keyed write requests to a delayed action queue; and processes the read queue and the delayed action queue to service the requests.

Abstract: In general, in one aspect, the invention relates to a method for servicing query requests in distributed systems. The method includes making a first determination, by a query node and in response to a query request, that a user data sub-region associated with a query request, obtaining, in response to the first determination and using a population table, a revisions map, where the revisions map specifies a version of the user data sub-region, and servicing the query request using the revisions map and data associated with the version of the user data sub-region.

Abstract: In general, in one aspect, the invention relates to a method for servicing query requests in distributed systems. The method includes making a first determination, by a query node and in response to a query request, that a user data sub-region associated with a query request, obtaining, in response to the first determination and using a population table, a revisions map, where the revisions map specifies a version of the user data sub-region, and servicing the query request using the revisions map and data associated with the version of the user data sub-region.

Abstract: In general, the invention relates to a method for servicing query requests. The method includes determining, by a first query node and in response to a first query request, a user data sub-region and a target sub-region associated with the first query request. The further includes identifying a first input sub-region of the target sub-region using a data flow graph, identifying a second query node associated with the first input sub-region, and issuing a second query request to the second query node to obtain data associated with the first input sub-region. The method further includes receiving, in response to the second query request, a second query result from the second query node, generating a first query result for the target sub-region using at least the second query result, and providing the first query result to an entity associated with the issuance of the first query request.

Abstract: Embodiments of the invention relate to a method for managing subscriptions. The method includes initiating execution of a first subscription, in response to the initiating, obtaining a first subscription barrier associated with a first subscription, making, using the first subscription barrier, a first determination to block execution of a first query request associated with the first subscription, and in response to the first determination, ceasing execution of the first subscription.