Based on their implementation, RedisGraph uses the tuple-at-a-time model to process queries. However, some operators allow tuples to be batched before executing the operators' logic; for instance, the Conditional Traverse operator allows tuples to be batched with the predefined size.
Graph-related operators are mainly implemented with GraphBLAS:SuiteSparse, a linear algebra package for implementing graph algorithms based on GraphBLAS. For example, the Conditional Traverse operator contains a breadth-first search traversal algorithm. The breadth-first search traversal algorithm uses matrix-matrix multiplication from GraphBLAS:SuiteSparse.
RedisGraph allows users to provide their stored procedures written in C. Each stored procedure must be provided and registered before compiling the RedisGraph module.
The valid stored procedure must contain a stored procedure name, a number of input arguments, an output specification (i.e., output data types, output field names), and three main routines. The three main routines include Invoke, Step, and Free. Invoke will be called first after the stored procedure is called. Then, Step will be called multiple times to produce a single result tuple per Step call. Finally, Free will be called to clean up allocated memory. Users may store the state of each procedure call between these routines using the private data pointer.