TiDB 3.0.6 Release Notes

Release date: November 28, 2019

TiDB version: 3.0.6

TiDB Ansible version: 3.0.6

TiDB

• SQL Optimizer
  • Fix the issue that the result is incorrect after the window function AST restores SQL text, for example, over w being mistakenly restored to over (w) #12933
  • Fix the issue of pushing down STREAM AGG() to doubleRead #12690
  • Fix the issue that quotes are incorrectly handled for SQL binding #13117
  • Optimize the select max(_tidb_rowid) from t scenario to avoid full table scans #13095
  • Fix the issue that the query result is incorrect when the query statement contains a variable assignment expression #13231
  • Fix the issue that the result is incorrect when the UPDATE statement contains both a sub-query and a generated column; fix the UPDATE statement execution error when this statement contains two same-named tables from different source databases #13350
  • Support _tidb_rowid for point queries #13416
  • Fix the issue that the generated query execution plan is incorrect, caused by incorrect usage of partitioned table statistics #13628
• SQL Execution Engine
  • Fix the issue that TiDB is incompatible with MySQL when handling invalid values of the year type #12745
  • Reuse Chunk in the INSERT ON DUPLICATE UPDATE statement to reduce the memory overhead #12998
  • Add the support for the JSON_VALID built-in function #13133
  • Support executing ADMIN CHECK TABLE on partitioned tables #13140
  • Fix the panic issue when FAST ANALYZE is executed on empty tables #13343
  • Fix the panic issue when executing FAST ANALYZE on an empty table that contains multi-column indexes #13394
  • Fix the issue that the estimated number of rows is greater than 1 when the WHERE clause contains an equal condition on the unique key #13382
  • Fix the issue that the returned data might be duplicated when Streaming is enabled in TiDB #13254
  • Extract the top N values from the count-min sketch to improve the estimation accuracy #13429
• Server
  • Make requests sent to TiKV fail quickly when the gRPC dial times out #12926
  • Add the following virtual tables: #13009
    • performance_schema.tidb_profile_allocs
    • performance_schema.tidb_profile_block
    • performance_schema.tidb_profile_cpu
    • performance_schema.tidb_profile_goroutines
  • Fix the issue that the kill command does not work when the query is waiting for pessimistic locking #12989
  • Do not do asynchronous rollback when acquiring pessimistic locking fails and the transaction only involves modifying a single key #12707
  • Fix the panic issue when the response for the request of splitting Regions is empty #13092
  • Avoid unnecessary backoff when PessimisticLock returns a locking error #13116
  • Modify the TiDB behavior for checking configurations by printing a warning log for unrecognized configuration option #13272
  • Support obtaining the binlog status of all TiDB nodes via the /info/all interface #13187
  • Fix the issue that goroutine might leak when TiDB kills connections #13251
  • Make the innodb_lock_wait_timeout parameter work in pessimistic transactions to control the lock wait timeout for pessimistic locking #13165
  • Stop updating pessimistic transaction TTL when pessimistic transactional queries are killed to prevent other transactions from waiting unnecessarily #13046
• DDL
  • Fix the issue that the execution result of SHOW CREATE VIEW in TiDB is inconsistent with that in MySQL #12912
  • Support creating View based on union, for example, create view v as select * from t1 union select * from t2 #12955
  • Add more transaction-related fields for the slow_query table: #13072
    • Prewrite_time
    • Commit_time
    • Get_commit_ts_time
    • Commit_backoff_time
    • Backoff_types
    • Resolve_lock_time
    • Local_latch_wait_time
    • Write_key
    • Write_size
    • Prewrite_region
    • Txn_retry
  • Use the table's COLLATE instead of the system's default charset in the column when a table is created and the table contains COLLATE #13174
  • Limit the length of the index name when creating a table #13310
  • Fix the issue that the table name length is not checked when a table is renamed #13346
  • Add the alter-primary-key configuration (disabled by default) to support adding/dropping the primary key in TiDB #13522

TiKV

• Fix the issue that the acquire_pessimistic_lock interface returns a wrong txn_size #5740
• Limit the writes for GC worker per second to reduce the impact on the performance #5735
• Make lock_manager accurate #5845
• Support innodb_lock_wait_timeout for pessimistic locking #5848
• Add the configuration check for Titan #5720
• Support using tikv-ctl to dynamically modify the GC I/O limit: tikv-ctl --host=ip:port modify-tikv-config -m server -n gc.max_write_bytes_per_sec -v 10MB #5957
• Reduce useless clean up requests to decrease the pressure on the deadlock detector #5965
• Avoid reducing TTL in pessimistic locking prewrite requests #6056
• Fix the issue that a missing blob file might occur in Titan #5968
• Fix the issue that RocksDBOptions might not take effect in Titan #6009

PD

• Add an ActOn dimension for each filter to indicate that each scheduler and checker is affected by the filter, and delete two unused filters: disconnectFilter and rejectLeaderFilter #1911
• Print a warning log when it takes more than 5 milliseconds to generate a timestamp in PD #1867
• Lower the client log level when passing unavailable endpoint to the client #1856
• Fix the issue that the gRPC message package might exceed the maximum size in the region_syncer replication process #1952

Tools

• TiDB Binlog
  • Obtain the initial replication timestamp from PD when initial-commit-ts is set to "-1" in Drainer #788
  • Decouple Drainer's Checkpoint storage from the downstream and support saving Checkpoint in MySQL or local files #790
  • Fix the Drainer panic issue caused by using empty values when configuring replication database/table filtering #801
  • Fix the issue that processes get into the deadlock status instead of exiting after a panic occurs because Drainer fails to apply binlog files to the downstream #807
  • Fix the issue that Pump blocks when it exits because of gRPC's GracefulStop #817
  • Fix the issue that Drainer fails when it receives a binlog which misses a column during the execution of a DROP COLUMN statement in TiDB (v3.0.6 or later) #827
• TiDB Lightning
  • Add the max-allowed-packet configuration (64 M by default) for the TiDB backend #248