TiDB Monthly Update for June 2020

Releases

We have four releases this month:

• TiDB 4.0.1 Release Notes

  • New features
    • Add the --advertise-status-addr start flag to specify the status address to advertise #8046
    • Support the internal proxy for the built-in TiDB Dashboard #2511
    • Support the TiDB new collation framework
  • Bug fixes

• TiDB 3.1.2 Release Notes

  • Bug fixes

• TiDB 3.0.15 Release Notes

  • New features
    • Support the admin recover index and admin check index statements on partitioned tables #17315 #17390
    • Add a policy in which PD performs scheduling in terms of the number of leaders #2479
    • Optimize the output of SHOW CREATE TABLE and add quotation marks to the partition name #16315
  • Bug fixes

• TiDB Cloud Beta

Blog posts

Siddon Tang, the Chief Architect at PingCAP, in his article TiDB 4.0 GA, Gearing You Up for an Unpredictable World with a Real-Time HTAP Database announces that TiDB 4.0 has reached general availability (GA).

In Announcing TiDB as a Service, Fully-Managed TiDB Offering, we are thrilled to announce the beta release of TiDB Cloud, the fully-managed TiDB service delivered by PingCAP.

VLDB 2020: TiDB, A Raft-based HTAP Database introduces how we will contribute our novel ideas on databases and distributed systems back to the academic community.

Wei Liu's article How We Improved TPC-C Performance by 50% and TPC-H Performance by 100% shows you how we significantly enhanced TiDB 4.0's TPC-C and TPC-H performance.

Brian Anderson has written Rust's Huge Compilation Units and Generics and Compile-Time in Rust to explore Rust's compile times within the context of TiKV, the key-value store behind the TiDB database.

Notable pull requests

Planner

• Support building the clustered index range for the table scan
• Support clustered indexes for the double read

DDL

• Fix the issue that ALTER TABLE EXCHANGE PARTITION does not work if the table has TiFlash replicas
• Add warnings for constraints and checks

TiDB Dashboard

• Provide a better UI for the multi-selection and the instance selection
• Support the headless mode
• Add the telemetry feature

Tools

• Support the pipelined restore in Backup & Restore (BR)
• Add the local backend in TiDB Lightning

Engine

• Split SSTs by Region boundaries
• Improve the TiKV Region size estimation by counting deleted tombstones
• Support dynamically changing rate-bytes-per-sec

Scheduling

• Support scattering Regions in stores with special engines (like TiFlash)
• Make the operator fail immediately if the leader is changed to RemovePeer
• Introduce StoreCandidates and replace RandomSelector
• Improve the way to set the store limit and deprecate store-balance-rate
• Set a suitable default store limit of the TiFlash stores

TiUP

• Enable TiFlash in TiUP Playground on Mac
• Support scaling-in and scaling-out in TiUP Playground

Notable issues

Planner

• To improve the correctness and robustness of the index selection

DDL

• To try to increase the success rate of pessimistic transaction commits with concurrent DDL operations
• To add placement rules for a table through the DDL statement
• To support adding multiple indexes in one statement

Tools

• To fix the issue that the DDL operation through CREATE DATABASE or CREATE TABLE gets wrong queries in BR
• To fix the duplicated replication when cyclic-replication is enabled in TiCDC

Engine

To support RocksDB-Cloud

Scheduling

• To reduce the difference of size amplification between the new node and the original node
• To increase the probability of balancing new Regions

TiUP

• To fetch manifests concurrently
• To reduce the memory usage when downloading components

Call for participation

Wanna participate with us? Take a look at the following help-wanted issues, which are mentoring available:

TiUP

• To add unit tests

DDL

• To allow the row function in TiDB expression indexes
• To fix the issue that SHOW TABLE t next_row_id shows dropped tables

Scheduling

• To support changing the store limit according to the label

Tools

• To add test cases for more data types in sync-diff-inspector

New contributors

We'd like to welcome the following new contributors to TiDB and thank them for their work!

tidb:

• raygift
• JmPotato
• lvvvl
• markjenny
• chanme
• xhebox
• songyzh

docs:

• littlesmilelove
• lidaobing

docs-cn:

• eastfisher
• HuGanghui
• lemontree8801

parser:

• chanme

pd:

• mgkanani
• sunzhuohang

This Month in TiKV

For more detailed and comprehensive information about TiKV, we have TiKV Monthly Update. The following covers June.

This Month in TiKV - June 2020