TiDB 3.1 RC Release Notes

Release date: April 2, 2020

TiDB version: 3.1.0-rc

TiDB Ansible version: 3.1.0-rc

New Features

• TiDB

  • Use the binary search to re-implement partition pruning for better performance #15678
  • Support using the RECOVER syntax to recover the truncated table #15460
  • Add the AUTO_RANDOM ID cache for retrying statements and recovering tables #15393
  • Support restoring the state of the AUTO_RANDOM ID allocator using the recover table statement #15393
  • Support YEAR, MONTH, and TO_DAY functions as the partitioning keys of the Hash partitioned table #15619
  • Add the table ID to the schema-change related tables only when keys need to be locked in the SELECT... FOR UPDATE statement #15708
  • Add the feature of automatically reading data from different roles according to the load balancing policy and add the leader-and-follower system variable to enable this feature #15721
  • Support dynamically updating the TLS certificate every time TiDB establishes a new connection to update expired client certificate without restarting the RPC client side #15163
  • Upgrade PD Client to support loading the latest certificate every time TiDB establishes a new connection #15425
  • Forcibly use the HTTPS protocol with the configured TLS certificates between a TiDB server and a PD server, or between two TiDB servers when cluster-ssl-* is configured #15430
  • Add the MySQL-compatible --require-secure-transport startup option to force the client to enable TLS authentication during the configuration #15442
  • Add the cluster-verify-cn configuration item. After configuration, the status service can only be used when with the corresponding CN certificate #15137

• TiKV

  • Support backing up data with the Raw KV API #7051
  • Support TLS authentication for the status server #7142
  • Support TLS authentication for the KV server #7305
  • Optimize the time to hold locks to improve the performance of backup #7202

• PD

  • Support scheduling learner using shuffle-region-scheduler #2235
  • Add commands in pd-ctl to configure Placement Rules #2306

• Tools

  • TiDB Binlog

    • Support TLS authentication between the components #931 #937 #939
    • Add the kafka-client-id configuration item in Drainer to configure Kafka's client ID #929

  • TiDB Lightning

    • Optimize the performance of TiDB Lightning #281 #275
    • Support TLS authentication for TiDB Lightning #270

  • Backup & Restore (BR)

    • Optimize the log output #189

• TiDB Ansible

  • Optimize the way the TiFlash data directories are created #1242
  • Add the Write Amplification monitoring item in TiFlash #1234
  • Optimize the error message of failed preflight checks when CPU epollexclusive is unavailable #1243

Bug Fixes

• TiDB

  • Fix the information schema error caused by frequently updating the TiFlash replica #14884
  • Fix the issue that last_insert_id is incorrectly generated when applying AUTO_RANDOM #15149
  • Fix the issue that updating the status of TiFlash replica might cause the DDL operation to get stuck #15161
  • Forbid Aggregation pushdown and TopN pushdown when there are predicates that cannot be pushed down #15141
  • Forbid the nested view creation #15440
  • Fix the error occurred when executing SELECT CURRENT_ROLE() after SET ROLE ALL #15570
  • Fix the failure to identify the view name when executing the select view_name.col_name from view_name statement #15573
  • Fix the issue that an error might occur when pre-processing DDL statements during the write of binlog information #15444
  • Fix the panic occurred when accessing both views and partitioned tables #15560
  • Fix the error occurred when executing the VALUES function with the update duplicate key statement that contains the bit(n) data type #15487
  • Fix the issue that the specified maximum execution time fails to take effect in some scenarios #15616
  • Fix the issue that whether the current ReadEngine contains TiKV server is not checked when generating the execution plan using Index Scan #15773

• TiKV

  • Fix the issue of conflict check failure or data index inconsistency caused by inserting an existing key into a transaction and then deleting it immediately when disabling the consistency check parameter #7112
  • Fix the calculation error when TopN compares unsigned integers #7199
  • Introduce a flow control mechanism in Raftstore to solve the problem that without flow control, it might cause slow log tracking and cause the cluster to be stuck; and the problem that the large transaction size might cause the frequent reconnection among TiKV servers #7087 #7078
  • Fix the issue that pending read requests sent to replicas might be permanently blocked #6543
  • Fix the issue that replica read might be blocked by applying snapshots #7249
  • Fix the issue that transferring leader might cause TiKV to panic #7240
  • Fix the issue that all SST files are filled with zeroes when backing up data to S3 #6967
  • Fix the issue that the size of SST file is not recorded during backup, resulting in many empty Regions after restoration #6983
  • Support AWS IAM web identity for backup #7297

• PD

  • Fix the issue of incorrect Region information caused by data race when PD processes Region heartbeats #2234
  • Fix the issue that random-merge-scheduler fails to follow location labels and Placement Rules #2212
  • Fix the issue that a placement rule is overwritten by another placement rule with the same startKey and endKey #2222
  • Fix the issue that the version number of API is inconsistent with that of PD server #2192

• Tools

  • TiDB Lightning

    • Fix the bug that the & character is replaced by the EOF character in TiDB backend #283

  • Backup & Restore (BR)

    • Fix the issue that BR cannot restore the TiFlash cluster data #194