maria-developers team mailing list archive

["jiangchengyao" <jiangchengyao@xxxxxxxxx>]

Yes, Logical IO means pages from buffer pool, physical IO means pages read from disk

2012-01-05



jiangchengyao



发件人：MARK CALLAGHAN
发送时间：2012-01-05 04:39
主题：Re: [Maria-developers] IO statistic in slow log
收件人：jiangchengyao
抄送：maria-developers

What are the difference between logical and physical IO? I assume you 
are using Oracle's terminology where a logical IO means that a page 
was read from the InnoDB buffer cache. 

On Thu, Dec 29, 2011 at 6:41 PM, jiangchengyao <jiangchengyao@xxxxxxxxx> wrote: 
> Hi, all 
> 
> I write a patch to show physical & logical IO statistics in slow log. Now it 
> only support XtraDB storage engine, but it is easy to realize in other 
> engine. You may found it like this in slow log: 
> 
> # Time: 111227 16:29:54 
> # User@Host: root[root] @ localhost [::1] 
> # Query_time: 0.310018  Lock_time: 0.203012 Rows_sent: 1  Rows_examined: 
> 30000 Logical_IO: 30145 Physical_IO: 50 
> use tpcc; 
> SET timestamp=1324974594; 
> select count(1) from history; 
> 
> I think this feature is much helpful for DBA or Developer to know what the 
> real IO one SQL has. In addition, it is simple, only a few changes should be 
> made. 
> 
> The branch is:  https://code.launchpad.net/~jiangchengyao/+junk/mariadb 
> 
> Regards, 
> David 
> 
> 2011-12-30 
> ________________________________ 
> jiangchengyao 
> 
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--  
Mark Callaghan 
mdcallag@xxxxxxxxx