3. The method according to claim 2 , wherein filtering out the second to-be-queried graph node in the graph data set and the association relationship in the graph data set comprising the second to-be-queried graph node in order to obtain the reduction subgraph comprises: reading a query node and a graph node matching the query node stored in storage space, wherein a query node in the query topology structure and a graph node matching the query node are stored in the storage space, wherein the query node comprises a start query node, wherein the graph node comprises the start graph node, and wherein the start graph node matches the start query node; determining whether the reduction subgraph comprises the read graph node; adding the read graph node to the reduction subgraph when the reduction subgraph does not comprise the read graph node; determining that the resource occupied by the reduction subgraph does not exceed the available resource condition; calculating an access cost of a to-be-queried graph node adjacent to the read graph node, and filtering out the second to-be-queried graph node whose access cost exceeds the first access cost and the association relationship comprising the second to-be-queried graph node whose access cost exceeds the first access cost, according to the query topology relationship between the query nodes in the query topology structure; and outputting, according to a preset dynamic reduction parameter, an access sequence that is to be stored into the storage space, wherein an access cost of a to-be-queried graph node in the access sequence does not exceed the first access cost, and wherein the preset dynamic reduction parameter controls a quantity of to-be-queried graph nodes in the access sequence.
2. The method according to claim 1 , wherein filtering out the second to-be-queried graph node in the graph data set and a corresponding association relationship to obtain the reduction subgraph comprises: generating a query topology structure according to the query condition, wherein the query topology structure comprises a plurality of query nodes and a query topology relationship between each query node and another query node in the plurality of query nodes; and filtering out, according to the query topology relationship between the query nodes in the query topology structure, a preset first access cost of accessing the first to-be-queried graph node, and the preset available resource condition, the second to-be-queried graph node in the graph data set whose access cost exceeds the preset first access cost and the association relationship in the graph data set comprising the second to-be-queried graph node in order to obtain the reduction subgraph, wherein a resource occupied by the reduction subgraph does not exceed the preset available resource condition.