MySQL Forums
Forum List  »  InnoDB

Re: Index exist on Deleted columns
Posted by: Peter Brawley
Date: September 20, 2017 10:19AM

If I'm reading your post correctly, innodb_buffer_pool_size is 23G in 8 GB of RAM. Yikes. When the buffer_pool is a quarter or so full, MySQL will be swapping to disk. Terrible. Swapping must be avoided. With 8GB RAM and no other software running, innonb_buffer_pool_size should be no more than 6GB.

There's probably a serious reason for that 23GB setting. Let's see the result of ...

select  
  concat(round(sum(table_rows)/1000000,2),'m') rows, 
  concat(round(sum(data_length)/(1024*1024*1024),2),'g') data, 
  concat(round(sum(index_length)/(1024*1024*1024),2),'g') idx, 
  concat(round(sum(data_length+index_length)/(1024*1024*1024),2),'g') total_size, 
  round(sum(index_length)/sum(data_length),2) idxfrac 
from information_schema.tables ;

show variables;
show global status;

The deletion cmd you posted would delete all rows. Much faster to truncate the table. Assuming the real query has a condition, best approach usually is to delete in chunks, see http://mysql.rjweb.org/doc.php/deletebig .

Options: ReplyQuote


Subject
Views
Written By
Posted
356
September 19, 2017 09:38AM
198
September 19, 2017 01:36PM
177
September 20, 2017 12:54AM
Re: Index exist on Deleted columns
196
September 20, 2017 10:19AM
205
September 21, 2017 04:21AM
187
September 21, 2017 09:27AM
199
September 22, 2017 05:12AM
204
September 22, 2017 09:04AM
193
September 24, 2017 07:14AM
190
September 24, 2017 11:13AM
179
September 24, 2017 09:29PM
178
September 24, 2017 09:55PM
177
September 25, 2017 12:25AM
179
September 25, 2017 11:03AM
169
September 26, 2017 05:30AM
186
September 26, 2017 12:12PM


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.