maria-developers team mailing list archive

[Arjen Lentz <arjen@xxxxxxxxxxxxx>]

Hi Vlad

On 06/04/2011, at 4:30 AM, Vladislav Vaintroub wrote:
> 3) innodb_log_file_size= min(innodb_buffer_pool_size/4, 50)
>
> I made this formula almost out of thin air and using some blog  
> reading and
> comments in the templates.  It is likely that 50M is more than the  
> average
> user needs, however it only takes some disk space, and  If user has to
> increase from default 5MB , the procedure is awkward.  I checked,  
> MySQL
> Config Wizard set this parameter to  54M on my box, so it is in  the  
> same
> range.

InnoDB also wants to have its log files at least 3x size of largest  
BLOB.

Given
 - Peter Laursen's sensible request to have 64M as a default  
max_packet_size;
 - combined witht  the small yet fixed amount of disk space the  
InnoDB log files use; and
 - the nuisance resizing the logfiles is,

I would suggest just fixing the size to either 50M or 64M, and not  
applying a magic formula to try and minimise it.
Given the little disk space it uses it doesn't serve that much of a  
purpose, and given that it's not relative to the buffer pool but also  
the transaction size, a simple formula just doesn't do the trick.


Yes I do realise that if Peter puts in a 50M BLOB, then the iblog  
should be >150M. But the packet size is all of a query, not just the  
one column, and it'll be escaped also. Regular BLOBs (images, etc)  
tend to not exceed 10M or so, which is well within the iblog/3 range  
for the size values I suggest.


Regards,
Arjen.
--
Arjen Lentz, Exec.Director @ Open Query (http://openquery.com)
Remote expertise & maintenance for MySQL/MariaDB server environments.

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