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Subject: Re: [boost] ACID transactions/flushing/MySQL InnoDB
From: Jose (jmalv04_at_[hidden])
Date: 2009-12-10 20:03:23

On Thu, Dec 10, 2009 at 11:02 PM, Stefan Strasser
<strasser_at_[hidden]> wrote:
> but, including all the SQL parsing, running 10000 small transactions takes
> about 4 seconds on my system.
> while this little code snippet alone takes 6-7 seconds, with much more disk
> usage:
>  int fd=open("test.bin",O_RDWR | O_CREAT | O_NOATIME);
>  for(int c=0;c<10000;++c){
>    write(fd,&data,1);
>    fsync(fd);
>  }
> neither fdatasync(), O_WRONLY, nor writing whole sectors instead of just a
> byte make a difference. MySQL also claims to use fsync on the page you
> linked.
> do you have an explanation for this?

Check this blog post and part II, where innodb developer explains some
of the "unknown" details:

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