Enhancements

• Performance optimization for avg() function
• Optimization for taosd startup speed
• Performance optimization for index module in case of over 1 million tables
• KeepColumnName functionality of 2.x was supported in 3.0
• "taosd -s" can dump detailed information of mnode
• "show transactions" command can output the operation in progress
• Disable join operation on non timestamp columns
• Log optimization of TDB module to downgrade the CPU usage of mnode

Fixed Bugs

• Some crash problems in taosd
• Some memory leaks in taosd and taosAdapter
• Deleted data can still be queried
• Schemaless writing are not accumulated in statistical data for writing
• Wrong result when matching with NCHAR
• Action output by show transactions command is wrong when a transaction fails
• Wrong result of max() on float column
• Some bugs in planner and query module