A MapReduce-based distributed system, wherein the system comprises a management node and a target computing node, wherein the management node is configured to: obtain M computing tasks, and establish a resource assessment model according to a data size of the M computing tasks; and send some computing tasks of the M computing tasks and information about the resource assessment model to the target computing node, wherein each computing task of the some computing tasks needs to be computed by using P computing stages, M is greater than 1, and P is greater than 1, a quantity of the some computing tasks is greater than or equal to 2; wherein the management node is further configured to: send an information, to the target computing node, about a respective initial computing resource allocated to each computing task of the some computing tasks; the target computing node is configured to: receive the some computing tasks and the information about the resource assessment model that are sent by the management node; and obtain the resource assessment model according to the information about the resource assessment model; and before executing each computing stage of the P computing stages of a target task, substitute input data of the computing stage into the resource assessment model to compute a resource size of a computing resource required for the computing stage; and perform computing of the computing stage by using a computing resource that is of the resource size and that is in a preset resource pool in the target computing node; wherein the target task is any one computing task of the some computing tasks; wherein the target computing node is further configured to: receive the information, sent by the management node, about the respective initial computing resource allocated to each computing task of the some computing tasks; and register, as a computing resource, into the preset resource pool according to the information about the respective initial computing resource, the respective initial computing resource allocated to each computing task of the some computing tasks. the management node is configured to: obtain M computing tasks, and establish a resource assessment model according to a data size of the M computing tasks; and send some computing tasks of the M computing tasks and information about the resource assessment model to the target computing node, wherein each computing task of the some computing tasks needs to be computed by using P computing stages, M is greater than 1, and P is greater than 1, a quantity of the some computing tasks is greater than or equal to 2; obtain M computing tasks, and establish a resource assessment model according to a data size of the M computing tasks; and send some computing tasks of the M computing tasks and information about the resource assessment model to the target computing node, wherein each computing task of the some computing tasks needs to be computed by using P computing stages, M is greater than 1, and P is greater than 1, a quantity of the some computing tasks is greater than or equal to 2; wherein the management node is further configured to: send an information, to the target computing node, about a respective initial computing resource allocated to each computing task of the some computing tasks; the target computing node is configured to: receive the some computing tasks and the information about the resource assessment model that are sent by the management node; and obtain the resource assessment model according to the information about the resource assessment model; and before executing each computing stage of the P computing stages of a target task, substitute input data of the computing stage into the resource assessment model to compute a resource size of a computing resource required for the computing stage; and perform computing of the computing stage by using a computing resource that is of the resource size and that is in a preset resource pool in the target computing node; wherein the target task is any one computing task of the some computing tasks; receive the some computing tasks and the information about the resource assessment model that are sent by the management node; and obtain the resource assessment model according to the information about the resource assessment model; and before executing each computing stage of the P computing stages of a target task, substitute input data of the computing stage into the resource assessment model to compute a resource size of a computing resource required for the computing stage; and perform computing of the computing stage by using a computing resource that is of the resource size and that is in a preset resource pool in the target computing node; wherein the target task is any one computing task of the some computing tasks; wherein the target computing node is further configured to: receive the information, sent by the management node, about the respective initial computing resource allocated to each computing task of the some computing tasks; and register, as a computing resource, into the preset resource pool according to the information about the respective initial computing resource, the respective initial computing resource allocated to each computing task of the some computing tasks.