Abstract: Efficiently implemented herein is a deterministic semantic for property updates by graph queries. Mechanisms of determinism herein ensure data consistency for graph mutation. These mechanisms facilitate optimistic execution of graph access despite a potential data access conflict. This approach may include various combinations of special activities such as detecting potential conflicts during query compile time, applying query transformations to eliminate those conflicts during code generation where possible, and executing updates in an optimistic way that safely fails if determinism cannot be guaranteed. In an embodiment, a computer receives a request to modify a graph. The request to modify the graph is optimistically executed after preparation and according to safety precautions as presented herein. Based on optimistically executing the request, a data access conflict actually occurs and is automatically detected.

Abstract: Efficiently implemented herein is a deterministic semantic for property updates by graph queries. Mechanisms of determinism herein ensure data consistency for graph mutation. These mechanisms facilitate optimistic execution of graph access despite a potential data access conflict. This approach may include various combinations of special activities such as detecting potential conflicts during query compile time, applying query transformations to eliminate those conflicts during code generation where possible, and executing updates in an optimistic way that safely fails if determinism cannot be guaranteed. In an embodiment, a computer receives a request to modify a graph. The request to modify the graph is optimistically executed after preparation and according to safety precautions as presented herein. Based on optimistically executing the request, a data access conflict actually occurs and is automatically detected.

Abstract: Herein are techniques to accelerate finding a top few shortest paths between two vertices of a graph. In an embodiment, a computer calculates, for a graph that contains vertices that include landmark vertices, distances between each vertex and each landmark vertex. Based on the distances from each vertex to each landmark vertex, a top few shortest paths from a source vertex to a target vertex are calculated. In an embodiment, triangulation establishes a lower bound on a distance from a neighbor vertex of a current vertex to a target vertex of a query. In an embodiment, distance predictions based on the distance lower bounds are used to accelerate a K-A star search for the top few shortest paths.