![PingCAP.com
Index Structure
Row:
Key: tablePrefix_rowPrefix_tableID_rowID (IDs are assigned by TiDB, all int64)
Value: [col1, col2, col3, col4]
Index:
Key: tablePrefix_idxPrefix_tableID_indexID_ColumnsValue_rowID
Value: [null]
Keys are ordered by byte array in TiKV, so can support SCAN
Every key is appended a timestamp, issued by Placement Driver](https://image.slidesharecdn.com/sfk8smeetup103018introducingtidb-181031180837/85/Presentation-at-SF-Kubernetes-Meetup-10-30-18-Introducing-TiDB-TiKV-34-320.jpg)
Presentation at SF Kubernetes Meetup (10/30/18), Introducing TiDB/TiKV
- 1. Introducing TiDB/TiKV Kevin Xu (@kevinsxu; [email protected])
- 2. Agenda ● History and Community ● Technical Walkthrough ● Use Case with Mobike ● Q&A ● (Time Permitting) TiDB on Google Kubernetes Engine
- 3. A little about me ● General Manager of Global Strategy and Operations ● Studied CS and Law at Stanford ● Program in Javascript, Python, and (more recently) learning Rust
- 4. A little about PingCAP ● Founded in April 2015 by 3 infrastructure engineers ● Offices throughout North America and China
- 6. PingCAP.com Our Product: the TiDB Platform ● TiDB Platform (Ti = Titanium) ○ TiDB (SQL Layer) ○ TiKV (Key-Value Storage) ○ TiSpark (Spark plugin to TiKV) ● Open source from Day 1 ○ GA 1.0: October 2017 ○ GA 2.0: April 2018
- 7. PingCAP.com Community Stars ● TiDB: 15,300+ ● TiKV: 3,700+ Contributors ● TiDB: 200+ ● TiKV: 100+
- 8. Common Use Cases 1. MySQL Scalability 2. Hybrid OLTP/OLAP Architecture 3. Unifying Data Storage/Management
- 10. PingCAP.com Cloud-Native Architecture TiDB TiDB TiDB Applicationvia MySQLProtocol TiKV TiKV TiKV TiKV TiKV TiKV Worker Worker Worker Spark Driver ... ... ... SparkSQL Spark Cluster PD Cluster DistSQL API KV API DistSQL API PD PD PD Metadata TSO / Data Location Data Location
- 11. PingCAP.com TiKV (in CNCF): The Storage Foundation Region 5 Region 1 Region 3 TiKV node 1 Store 1 Region 4 gRPC Region 1 Region 2 TiKV node 2 Store 2 Region 3 gRPC Region 3 Region 1 Region 5 TiKV node 3 Store 3 gRPC Region 5 Region 1 Region 2 TiKV node 4 Store 4 gRPC Client PD 1 PD 2 PD 3 Placement Driver Raft GroupRegion 4 Region 4
- 12. PingCAP.com TiDB: The (My)SQL Layer Node1 Node2 Node3 Node4 MySQL Network Protocol SQL Parser Cost-based Optimizer Coprocessor API ODBC/JDBC MySQL Client Any ORM which supports MySQL TiDB TiKV
- 13. PingCAP.com SQL -> Parser -> Coprocessor
- 14. PingCAP.com Join Support ● Hash Join (fastest; if table <= 50 million rows) ● Sort Merge Join (join on indexed column or ordered data source) ● Index Lookup Join (join on indexed column; ideally after filter, result < 10,000 rows) ● Chosen based on Cost-base Optimizer:
- 15. PingCAP.com TiSpark: Complex OLAP Spark ExecSpark Exec Spark Driver Spark Exec TiKV TiKV TiKV TiKV TiSpark TiSpark TiSpark TiSpark TiKV Placement Driver (PD) gRPC Distributed Storage Layer gRPC retrieve data location retrieve real data from TiKV
- 16. PingCAP.com Placement Driver ● Provide a God’s view of the entire cluster ● Store metadata, balancing workload, issue timestamps ● Also a cluster with embedded etcd Placement Driver Placement Driver Placement Driver Raft Raft Raft
- 17. PingCAP.com Transaction Model ● Timestamp Oracle Service (from Google’s Percolator) ● 2-Phase commit protocol (2PC) ● Problem: Single point of failure ● Solution: PD HA cluster Placement Driver Placement Driver Placement Driver Raft Raft Raft
- 18. PingCAP.com TiDB Operator ● Operator pattern inspired by CoreOS...(now Redhat...(now IBM)) ● Boostraps TiDB cluster and simplifies/automates: ○ Deployment ○ Scaling ○ Scheduling ○ Auto-Failover ○ Upgrade ● Open Sourced ○ https://github.com/pingcap/tidb-operator
- 19. PingCAP.com TiDB Operator API ServerController ManagerScheduler Kubernetes Core TiDB Controller Manager TiDB Cluster Controller PD Controller TiKV Controller TiDB Controller TiDB Scheduler: TiDB Cloud Manager API Gateway Control Plane Cost Controller Kube Scheduler TiDB Scheduler
- 20. PingCAP.com Cloud Native Tools ● Prometheus ○ (maintains Rust implementation: https://github.com/pingcap/rust-prometheus) ● gRPC ○ (maintains Rust implementation: https://github.com/pingcap/grpc-rs) ● etcd
- 21. PingCAP.com TiDB, Managed As A Cloud Service Early Access: https://www.pingcap.com/tidb-cloud/
- 24. Common Use Cases 1. MySQL Scalability 2. Hybrid OLTP/OLAP Architecture 3. Unifying Data Storage/Management
- 25. PingCAP.com Mobike + TiDB ● 200 million users ● 200 cities ● 9 million smart bikes ● ~30 TB / day
- 26. PingCAP.com Scenario #1: Locking/Unlocking ● Locking and unlocking of smart bikes generates massive data ● Smooth experience is the key to user retention ● TiDB supports this system by alerting administrators when the success rate of locking/unlocking drops, within minutes ● Quickly find malfunctioning bikes
- 27. PingCAP.com Scenario #2: Real-Time Analysis ● Synchronize TiDB with MySQL instances using Syncer (proprietary tool) ● TiDB + TiSpark empower real-time analysis with horizontal scalability ● No need for Hadoop + Hive
- 28. PingCAP.com Scenario #3: Mobike Store ● An innovative loyalty program that must be on 24x7x365 ● TiDB provides: ○ High-concurrency for peak or promotional season ○ Permanent storage ○ Horizontal scalability ● No interruption as business evolves
- 29. PingCAP.com Thank You! 20% OFF KubeCon: KCNA18SPR [email protected] @kevinsxu; @pingcap TiDB Cloud Early Access: https://www.pingcap.com/ tidb-cloud/ TiDB Academy Sign-up: www.pingcap.com/tidb-ac ademy/
- 30. Appendix
- 31. PingCAP.com CBO 101 or: Imagine we got a logical plan: Its physical plan could be:
- 32. PingCAP.com CBO 101 Network cost Memory cost CPU cost In TiDB, the default memory factor is 5 and CPU factor is 0.8. For example: Operator Sort(r), its cost would be: TiDB will maintain histogram of data
- 33. PingCAP.com Relational -> KV ID Name Email 1 Edward [email protected] 2 Tom [email protected] ... user/1 Edward,[email protected] user/2 Tom,[email protected] ... In TiKV -∞ +∞ (-∞, +∞) Sorted map “User” Table Some region...
- 34. PingCAP.com Index Structure Row: Key: tablePrefix_rowPrefix_tableID_rowID (IDs are assigned by TiDB, all int64) Value: [col1, col2, col3, col4] Index: Key: tablePrefix_idxPrefix_tableID_indexID_ColumnsValue_rowID Value: [null] Keys are ordered by byte array in TiKV, so can support SCAN Every key is appended a timestamp, issued by Placement Driver
- 35. PingCAP.com Guaranteeing Correctness ● Formal proof using TLA+ ○ a formal specification and verification language to reason about and prove aspects of complex systems ● Raft ● TSO/Percolator ● 2PC ● See details: https://github.com/pingcap/tla-plus
- 36. PingCAP.com MySQL Compatibility - Summary ● Compatibility with MySQL 5.7 ○ Joins, subqueries, DML, DDL etc. ● On the roadmap: ○ Views, Window Functions ● Missing: ○ Stored Procedures, Triggers, Events, Fulltext pingcap.com /docs/sql/mysql-compatibility/
- 37. PingCAP.com MySQL Compatibility - Nuanced ● Some features work differently ○ Auto Increment ○ Optimistic Locking ● TiDB works better with smaller transactions ○ Recommended to batch updates, deletes, inserts to 5000 rows pingcap.com /docs/sql/mysql-compatibility/