This is the speech Siddon Tang gave at the 1st Rust Meetup in Beijing on April 16, 2017. Siddon Tang：Chief Architect of PingCAP The slide covered the following topics: - Why do we use Rust in TiKV - TiKV architecture introduction - Key technology - Future plan

1. Rust in TiKV
tl@pingcap.com

2. About me
● Tang Liu
● Chief Architect of PingCAP
● Worked at Kingsoft and Tencent
● Open sources: LedisDB, go-mysql, etc.

3. Agenda
● Why do we use Rust in TiKV
● TiKV architecture introduction
● Key technology
● Future plan

4. What’s TiKV?
A distributed Key-Value database with:
● Geo-Replication
● Horizontal scalability
● Consistent distributed transaction
● Coprocessor for distributed computing
● Working with TiDB like Spanner with F1

5. We need a language with:
● Fast speed
● Memory safety
● Thread safety
● Binding C efficiency

6. Why not C++?
● Memory leak, dangling pointer, etc.
● Data race
● No official package manager
● Development cycle will be long...

7. Why not Go?
● GC
● Data race
● Goroutine runtime expenses
● CGO expenses

8. So we turned to Rust...

9. But Rust...
● Steep learning curve
● Long compiling time
● Lack of libraries and tools
● Few programmers know it in
China
Time
Rust
Learning Curve

10. Why Rust?
● Memory safety
● Thread safety
● No GC
● Calling C is fast
● Official package manager

11. We made a hard but great decision:
Use Rust!

12. TiKV Timeline
Start
2016-01-01
Open Source
2016-04-01
Production
2016-10
Beta4
2016-11
RC1
2016-12
GA
2017-11
RC3
2017-04
RC2
2017-02

13. TiKV Architecture
KV API Coprocessor
Transaction
MVCC
Raft KV
RocksDB

14. Multi-Raft
Region 1
Region 3
Region 5
Region 4
Region 3
Region 5
Region 2Region 1
Region 3
Region 2
Region 4
Region 1
Region 5
Region 2
Region 4
TiKV node 1 TiKV node 2 TiKV node 3 TiKV node 4
Raft
Group

15. Region 1
Region 3
Region 1
Region 2
Scale-out (initial state)
Region 1*
Region 2 Region 2
Region 3Region 3
Node A
Node B
Node C
Node D

16. Region 1
Region 3
Region 1^
Region 2
Region 1*
Region 2 Region 2
Region 3Region 3
Node A
Node B
Node E
1) Transfer leadership of “region 1” from Node A to Node
B
Node C
Node D
Scale-out (add new node)

17. Region 1
Region 3
Region 1*
Region 2
Region 2 Region 2
Region 3
Region 1
Region 3
Node A
Node B
2) Add Replica on Node E
Node C
Node D
Node E
Region 1
Scale-out (balancing)

18. Region 1
Region 3
Region 1*
Region 2
Region 2 Region 2
Region 3
Region 1
Region 3
Node A
Node B
3) Remove Replica from Node A
Node C
Node D
Node E
Scale-out (balancing)

19. Client
TiKV
KV Thread
Raft Thread
RocksDB
Request
Request
Request
Log TiKV Node
Log TiKV Node
Log TiKV Node
Data
Parse the
protocol
Apply the log
A simple
write flow
Executes the
transaction logic

20. Key technology
● Networking
○ Protocol Buffers (protobuf)
○ mio
○ gRPC
● Asynchronous framework
○ mio + callback
○ tokio-core + futures
○ thread pool + futures - cpupool

21. Key technology
● Storage
○ rust-rocksdb
● Monitoring tool
○ rust-prometheus
● Profile tool
○ jemallocator with prof feature
● Lint tool
○ clippy

22. TODO...
● Make TiKV more fast, like removing Box
● Make TiKV more stable, like introducing Rust sanitizer
● Contribute more Rust open source modules, like raft library, open-tracing, etc.
● Participate in other Rust projects more deeply, like rust-gRPC
● Write more articles about Rust on Chinese social media and organize more
Rust meetups
● Be a strong advocate of Rust in China

23. Thank you!