MySQL sharding approaches?

Question

What is the best approach for Sharding MySQL tables. The approaches I can think of are :

1. Application Level sharding?
2. Sharding at MySQL proxy layer?

Answer 1

As of 2018, there seems to be a MySql-native solution to that. There are actually at least 2 - InnoDB Cluster and NDB Cluster(there is a commercial and a community version of it).

Since most people who use MySql community edition are more familiar with InnoDB engine, this is what should be explored as a first priority. It supports replication and partitioning/sharding out of the box and is based on MySql Router for different routing/load-balancing options.

The syntax for your tables creation would need to change, for example:

    CREATE TABLE t1 (col1 INT, col2 CHAR(5), col3 DATETIME) PARTITION BY HASH ( YEAR(col3) );

(this is only one of four partitioning types)

One very important limitation:

InnoDB foreign keys and MySQL partitioning are not compatible. Partitioned InnoDB tables cannot have foreign key references, nor can they have columns referenced by foreign keys. InnoDB tables which have or which are referenced by foreign keys cannot be partitioned.