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tidb-server v2.1.0-beta
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@shenli shenli released this 29 Jun 15:06
· 18635 commits to master since this release
v2.1.0-beta
dd37138
  • SQL Optimizer
    • Optimize the selection range of Index Join to improve the execution performance
    • Optimize correlated subquery, push down Filter, and extend the index range, to improve the efficiency of some queries by orders of magnitude
    • Support Index Hint and Join Hint in the UPDATE and DELETE statements
    • Validate Hint TIDM_SMJ when no available index exists
    • Support pushdown of the ABS, CEIL, FLOOR, IS TRUE, and IS FALSE functions
    • Handle the IF and IFNULL functions especially in the constant folding process
  • SQL Execution Engine
    • Implement parallel Hash Aggregate operators and improve the computing performance of Hash Aggregate by 350% in some scenarios
    • Implement parallel Project operators and improve the performance by 74% in some scenarios
    • Read the data of the Inner table and Outer table of Hash Join concurrently to improve the execution performance
    • Fix incorrect results of INSERT … ON DUPLICATE KEY UPDATE … in some scenarios
    • Fix incorrect results of the CONCAT_WS, FLOOR, CEIL, and DIV built-in functions
  • Server
    • Add the HTTP API to scatter the distribution of table Regions in the TiKV cluster
    • Add the auto_analyze_ratio system variable to control the threshold value of automatic Analyze
    • Add the HTTP API to control whether to open the general log
    • Add the HTTP API to modify the log level online
    • Add the user information in the general log and the slow query log
    • Support the server side cursor
  • Compatibility
    • Support more MySQL syntax
    • Make the bit aggregate function support the ALL parameter
    • Support the SHOW PRIVILEGES statement
  • DML
    • Decrease the memory usage of the INSERT INTO SELECT statement
    • Fix the performance issue of PlanCache
    • Add the tidb_retry_limit system variable to control the automatic retry times of transactions
    • Add the tidb_disable_txn_auto_retry system variable to control whether the transaction tries automatically
    • Fix the accuracy issue of the written data of the time type
    • Support the queue of locally conflicted transactions to optimize the conflicted transaction performance
    • Fix Affected Rows of the UPDATE statement
    • Optimize the statement performance of insert ignore on duplicate key update
  • DDL
    • Optimize the execution speed of the CreateTable statement
    • Optimize the execution speed of ADD INDEX and improve it greatly in some scenarios
    • Fix the issue that the number of added columns by Alter table add column exceeds the limit of the number of table columns
    • Fix the issue that DDL job retries lead to an increasing pressure on TiKV in abnormal conditions
    • Fix the issue that TiDB continuously reloads the schema information in abnormal conditions
    • Do not output the FOREIGN KEY related information in the result of SHOW CREATE TABLE
    • Support the select tidb_is_ddl_owner() statement to facilitate judging whether TiDB is DDL Owner
    • Fix the issue that the index is deleted in the Year type in some scenarios
    • Fix the renaming table issue in the concurrent execution scenario
    • Support the AlterTableForce syntax
    • Support the AlterTableRenameIndex syntax with FromKey and ToKey
    • Add the table name and database name in the output information of admin show ddl jobs
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