How does SingleStoreDB shard tables?

Every distributed table (except reference tables, which are replicated in whole on each “leaf” node) has a SHARD KEY that specifies which columns of a row to hash to determine what partition a row should reside in. When rows are inserted into a sharded table, they are hashed by the table’s shard key and sent to the leaf carrying the corresponding partition. This technique is commonly referred to as hash-based partitioning. You can choose how to shard each table by specifying its SHARD KEY as part of the CREATE TABLE statement. See Sharding for more details.