Low performance when I run last_row + group by tbname in TDengine databases

Question

this is my SQL:

select last_row(*) from test.meters where ts now-100d group by tbname;

I have 100000000 rows of data ,and it cost me 11 seconds. like this :

I don't think it is the best performance ,may I know how to improve it .

Answer 1

please run this command in TDengine database shell :

select * from information_schema.ins_databases\G;

to check if 'cachemodel' is none ,if it is , set it to 'both'

Then try again.