Re: bk commit into 5.0 tree (gkodinov:1.2521) BUG#29325

[Guilhem Bichot]

Hello,

On Wed, Jul 11, 2007 at 10:49:57AM +0300, kgeorge@stripped wrote:
> ChangeSet@stripped, 2007-07-11 10:49:54+03:00, gkodinov@stripped +9 -0
>   Bug #29325: 
>   By default MyISAM overwrites .MYD and .MYI files no 
>   DATA DIRECTORY option is used. This can lead to two tables
>   using the same .MYD and .MYI files (that can't be dropped).
>   
>   To prevent CREATE TABLE from overwriting a file a new option
>   is introduced : keep_files_on_create
>   When this is on the CREATE TABLE throws an error if either
>   the .MYD or .MYI exists for a MyISAM table.
>   The option is off by default (resulting in compatible behavior).

> diff -Nrup a/myisam/mi_create.c b/myisam/mi_create.c
> --- a/myisam/mi_create.c	2007-03-13 16:05:10 +02:00
> +++ b/myisam/mi_create.c	2007-07-11 10:49:53 +03:00
> @@ -586,7 +586,8 @@ int mi_create(const char *name,uint keys
>  					     32 : 0));
>      linkname_ptr=0;
>      /* Replace the current file */
> -    create_flag=MY_DELETE_OLD;
> +    if (!(flags & HA_CREATE_KEEP_FILES))
> +      create_flag=MY_DELETE_OLD;
>    }
>  
>    /*
> @@ -647,7 +648,8 @@ int mi_create(const char *name,uint keys
>        {
>  	fn_format(filename,name,"",MI_NAME_DEXT,4);
>  	linkname_ptr=0;
> -	create_flag=MY_DELETE_OLD;
> +        if (!(flags & HA_CREATE_KEEP_FILES))
> +          create_flag=MY_DELETE_OLD;
>        }
>        if ((dfile=
>  	   my_create_with_symlink(linkname_ptr, filename, 0, create_mode,

ha_myisam::create() and mi_create() are also called in case of
TRUNCATE TABLE (destroying old data and index files as it creates new
empty ones). I wonder if it could fail now, with the new option on.
Could you please verify, with the new option on and a simple table
like this:

create table t(a int) engine=myisam;
insert into t values(1);
truncate table t;

that TRUNCATE still works, and if it works, add this in a .test file?

Thank you!

-- 
   __  ___     ___ ____  __
  /  |/  /_ __/ __/ __ \/ /    Mr. Guilhem Bichot <guilhem@stripped>
 / /|_/ / // /\ \/ /_/ / /__   MySQL AB, Lead Software Engineer
/_/  /_/\_, /___/\___\_\___/   Bordeaux, France
       <___/   www.mysql.com