Data writing method, memory controller and memory storage apparatus

A memory controller for controlling a rewritable non-volatile memory module, the memory controller comprising:

• a host interface, coupled to a host system;
• a memory interface coupled to the rewritable non-volatile memory module, wherein the rewritable non-volatile memory module includes a plurality of physical erasing units, each of the physical erasing units includes a plurality of physical programming units, the physical erasing units are grouped into at least a data area and a spare area, the physical erasing units of the spare area are used for substituting the physical erasing units of the data area to write data;
• and
• a memory management circuit coupled to the host interface and the memory interface, wherein the memory management circuit is configured to configure a plurality of logical units for mapping to the physical erasing units of the data area, wherein each of the logical units includes a plurality of logical pages,
• wherein the memory management circuit is configured to select at least one physical erasing unit from the spare area as a global random area, wherein the global random area temporarily stores data belonging to a plurality of updated logical pages, and the updated logical pages belong to a plurality of updated logical units among the logical units,
• wherein the memory management circuit is further configured to build a global random area searching table to record a plurality of updated information corresponding to the updated logical pages in the global random area,
• wherein the memory management circuit is further configured to receive a write command and an updated data corresponding to the write command, wherein the updated data belongs to a first logical page and the first logical page belongs to a first logical unit among the logical units,
• wherein the memory management circuit is further configured to record a data dispersedness degree corresponding to the global random area and determine whether the data dispersedness degree corresponding to the global random area is smaller than a data dispersedness degree threshold,
• wherein If the data dispersedness degree corresponding to the global random area is smaller than the data dispersedness degree threshold, the memory management circuit writes the updated data into the global random area and records updated information corresponding to the first logical page in the global random area searching table.

A memory storage apparatus, comprising:

• a connector coupled to a host system;
• a rewritable non-volatile memory module including a plurality of physical erasing units, wherein each of the physical erasing units includes a plurality of physical programming units, the physical erasing units are at least grouped into a data area and a spare area, and the physical erasing units of the spare area are used for substituting the physical erasing units of the data area to write data;
• and
• a memory controller coupled to the connector and the rewritable non-volatile memory module, wherein the memory controller is configured to configure a plurality of logical units for mapping to the physical erasing units of the data area, wherein each of the logical units includes a plurality of logical pages,
• wherein the memory controller is configured to select at least one physical erasing unit from the spare area as a global random area, wherein the global random area temporarily stores data belonging to a plurality of updated logical pages, and the updated logical pages belong to a plurality of updated logical units among the logical units,
• wherein the memory controller is configured to build a global random area searching table to record a plurality of updated information corresponding to the updated logical pages in the global random area,
• wherein the memory controller is further configured to receive a write command and an updated data corresponding to the write command, wherein the updated data belongs to a first logical page and the first logical page belongs to a first logical unit among the logical units,
• wherein the memory controller is further configured to record a data dispersedness degree corresponding to the global random area and determine whether the data dispersedness degree corresponding to the global random area is smaller than a data dispersedness degree threshold,
• wherein If the data dispersedness degree corresponding to the global random area is smaller than the data dispersedness degree threshold, the memory controller writes the updated data into the global random area and records updated information corresponding to the first logical page in the global random area searching table.