The PD follower then forwards the TSO requests to reduce the CPU pressure of PD leader. When this feature is enabled, TiDB evenly sends the requests to all PD nodes when acquiring TSO. At this time, TiDB only gets TSO from PD leader. The default value is OFF, which means the TSO Follower Proxy feature is disabled. When you set the value as OFF, even if the statistics expire, the optimizer still uses them.ĭetermines whether to enable or disable the TSO Follower Proxy feature. When the number of modified rows in the table is greater than 80% of the total rows (This ratio can be adjusted by the configuration pseudo-estimate-ratio), the optimizer considers that the statistics other than the total number of rows are no longer reliable and use pseudo statistics instead.
Temporary tables are now supported by TiDB so CREATE TEMPORARY TABLE and DROP TEMPORARY TABLE no longer require enabling tidb_enable_noop_functions.Ĭontrols the behavior of the optimizer when the statistics on a table expire. When upgrading from an earlier TiDB version to v5.3.0, if you want to know the compatibility change notes of all intermediate versions, you can check the Release Notes of the corresponding version. Reduce the write latency of TiKV by separating I/O operations from Raftstore thread pool (disabled by default).Continue optimizing the storage and computing engines to improve the system performance and stability.Support the continuous profiling experimental feature to improve the observability of database performance.Support saving and restoring the on-site information of a cluster with a single SQL statement, which helps improve the efficiency of troubleshooting issues relating to execution plans.Support parallel import using multiple TiDB Lightning instances to improve the efficiency of full data migration.Enhance the performance of TiDB Data Migration (DM) so that data is migrated from MySQL to TiDB with lower latency.Optimize the timestamp processing flow in TiDB to improve the overall performance.Support creating users with the least privileges on TiDB Dashboard to enhance system security.Support setting attributes for tables and partitions.Introduce temporary tables to simplify your application logic and improve performance.In v5.3, the key new features or improvements are as follows:
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