Improve the kernel processor

[terrymanu]

As you know, ShardingSphere can support horizontal and vertical sharding with federation query engine.

Now, I want to discuss how to improve the current ShardingSphere kernel.

My question and solution is below:

Problem

1. The module single-table-core is in kernel which is required, but sharding-core is pluggable, they are not equivalence.

2. The name of these 2 modules are not good enough.

Solution

1. Merge single-table and sharding module:
   Move single-table into sharding module, and name original sharding as horizontal-sharding, name original single-table as vertical-sharding. Move the sharding module from pluggable feature to kernel.

2. Redesign table metadata domain:
   Rename single-table as table-metadata, hold all tables metadata, each table should contain related rules which decorated and merge from table metadata loading.

Which solution is better, or other new ideas?

[gwqlovelinux]

2

[MingJunDuan]

Nice work!