MySQL Forums
Forum List  »  Performance

Re: Bad performance on MySQL 8.0 compared to 5.7
Posted by: Peter Brawley
Date: August 16, 2022 10:04AM

8.0 does more, so it needs more resources than 5.7, so I'd need to see the results, in each MySQL instance, of ...

show global status;

select * from sys.memory_global_total;

select 
  substring_index(event_name,'/',2) as code_area, 
  sys.format_bytes( sum(current_alloc) ) as current_alloc 
from sys.x$memory_global_by_current_bytes 
group by substring_index(event_name,'/',2) 
order by sum(current_alloc) desc;

select concat(format(a.num * 100.0 / b.num,2),"%") bufferpoolfullpct 
from 
  (select variable_value num from performance_schema.global_status
  where variable_name = 'innodb_buffer_pool_pages_data') a,
  (select variable_value num from performance_schema.global_status
  where variable_name = 'innodb_buffer_pool_pages_total') b;

And please post the results of running this query in one of the MySQL instances ...

select engine,data,indexes,total
from (
  select 
    ifnull(engine,'TOTALS') as engine, 
    concat(data,' GB') as data, 
    concat(indexes,' GB') as indexes, 
    concat(tot,' GB') as total,
    if(engine is null,-1,tot) as ord
  from (
    select   
      engine,  
      round( sum(data_length)/1024/1024/1024, 2 ) as data,  
      round( sum(index_length)/1024/1024/1024, 2 ) as indexes,  
      round( sum(data_length+index_length)/1024/1024/1024, 2 ) as tot
    from information_schema.tables
    where engine is not null and engine not in('information_schema','performance_schema')
    group by engine with rollup
  ) sums
) list
order by list.ord desc;



Edited 1 time(s). Last edit at 08/16/2022 10:04AM by Peter Brawley.

Options: ReplyQuote


Subject
Views
Written By
Posted
Re: Bad performance on MySQL 8.0 compared to 5.7
42
August 16, 2022 10:04AM


Sorry, only registered users may post in this forum.

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.