1. A system comprising: one or more processors; memory communicatively coupled to the one or more processors; one or more ingest nodes configured to, when executed by the one or more processors, perform operations comprising: analyzing a record of a continuous data stream; generating one or more graph-update operations based on the record; assigning a sequence number to the one or more graph-update operations; and distributing the one or more graph-update operations to one or more graph nodes; a global progress table stored in the memory and configured to record sequence numbers assigned to the one or more graph-update operations, the global progress table comprising a vector including the sequence number and another sequence number, the sequence number and the other sequence number being assigned by different ingest nodes of the one or more ingest nodes; a snapshooter stored in the memory and configured to, when executed by the one or more processors, define an end of an epoch based on the global progress table; and the one or more graph nodes configured to, when executed by the one or more processors, perform operations comprising: storing the one or more graph-update operations in a storage layer of the one or more graph nodes; and producing a graph structure snapshot by executing the one or more graph-update operations that are stored in the storage layer and are within the epoch.