Re: Very slow performance when inserting, updating, deleting and changing schema

[Peter Brawley]

Esp. for big DBs, innodb_buffer_pool_size needs to 70-75% of available RAM, and for best p[erformance, you want enough RAM for any given DB to fit entirely in RAM.

Let's see 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;