Memory system and operating method thereof

A memory system comprising:

• a memory device comprising a state counter configured to generates a count result by counting a number of memory cells included in each a plurality of threshold voltage sections, based on data output from a page buffer group and provide the count result to a control logic;
• a memory interface configured to provide a read command to the memory device and receive data, which are acquired by read operations on a selected page, based on the read command;
• and
• a read retry unit configured to select a read retry set to be used to read data stored in the selected page among a plurality of read retry sets based on the numbers of memory cells respectively included in the plurality of threshold voltage sections.

A method for memory controller controlling a memory device including a plurality of memory blocks including memory cells, respectively, the method comprising:

• providing a user read command;
• receiving first data and second data, which are acquired by read operations on a selected page among the plurality of memory blocks, using first read voltages and second read voltages, in response to the user read command;
• counting numbers of memory cells of the selected page respectively included in a plurality of threshold voltage regions divided by the first read voltages and the second read voltages;
• reordering a read retry set among a plurality of read retry sets based on the numbers of memory cells;
• and
• controlling the memory device to perform a read retry operation selecting the read retry set having higher priority.