MySQL Forums
Forum List  »  General

Re: Mysql 8.0: High CPU Usage
Posted by: Peter Brawley
Date: November 04, 2019 10:48AM

8.0 is a bigger, more ambitious package than 5.7, places a few percent more demands on mem & cpu.

The numbers you posted suggest a system running at the edge of hardware capacities.

To explore it further please ...

(i) post the result of ...

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;

(ii) post the results of running these queries in the mysql client program ...

show variables;

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;
[/code]

... and look for runaway mem use in the results of ...

select * 
from performance_schema.memory_summary_global_by_event_name
where event_name like 'memory/performance_schema/%';

Options: ReplyQuote


Subject
Written By
Posted
November 02, 2019 09:33AM
November 02, 2019 10:57AM
November 04, 2019 03:46AM
Re: Mysql 8.0: High CPU Usage
November 04, 2019 10:48AM


Sorry, you can't reply to this topic. It has been closed.

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.