Write down the first version of Understanding TiDB chapter

[tisonkun]

• Write down the first version of The Lifecycle of a Statement section #56
  • Write down the first version of DDL section #55
  • Write down the first version of DML section #86
  • Write down the first version of DQL section #87
• Write down the first version of Parser section #88
• Write down the first version of Intro of Planner section #89
  • Write down the first version of Table Statistics section #58
  • Write down the first version of Rule-based Optimization section #59
  • Write down the first version of Cost-based Optimization section #80
  • Write down the first version of Plan Cache section #90
  • Write down the first version of SQL Plan Enhancement section #91
• Write down the first version of Intro of Execution section #57
  • Write down the first version of Execution Framework section #92
  • Write down the first version of Implementation of Vectorized Execution section #93
  • Write down the first version of Memory Management Mechanism section #94
  • Write down the first version of Implementation of Typical Operators section #95
• Write down the first version of The Overview of Transaction section #74
  • Write down the first version of Transaction on TiKV #150
  • Write down the first version of Optimistic Transaction #114
  • Write down the first version of Pessimistic Transaction #115
  • Write down the first version of Lock Resolver #116
  • Write down the first version of Async Commit #117
  • Write down the first version of 1PC #118
  • Write down the first version of MVCC Garbage Collection #119
• Write down the first version of Session section #54
• Write down the first version of Privilege section #53
• Write down the first version of Plugin section #61

[LittleFall]

What is the difference between DDL, DML, DQL chapters here and the corresponding chapters in TiDB documents?

[tisonkun]

@LittleFall I think they share a lot process described in "The Lifecycle of a Statement", but the section focuses on the differnece.

For example, DDL creates tables or drop tables, which updates the metadata which DQL doesn't touch. DQL will have a complex optimization and execution phase.

cc @mjonss @you06 @mengxin9014

[you06]

@tisonkun I created the issues for transaction sections, can you help to assign these issues and add them to the tracing list?

[tisonkun]

@you06 updated.

[tisonkun]

I think the mentioned candidate can comment directly and I'll assign if they ask for it explicitly.