From: Karen Abgarian <abvk
Date: November 24 2012 10:40pm
Subject: Re: Covering Index without the data file (myisam)
List-Archive: http://lists.mysql.com/mysql/228723
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Hello, 

Well, you have just invented what is known as index organized tables.   The MyISAM engine does not implement those. 
If it did, it would have to deal with quite a few circumstances unique to IOTs.    One such circumstance is degradation 
of efficiency with the increase of record length, another is bloating the size of secondary indexes, and there is quite a few more...

In short, the alternative to keeping the MYD file would be much worse :-) 

Peace
Karen.

On 24.11.2012, at 13:02, Hank wrote:

> Hello everyone,
> 
> I know this is a longshot, but is there any way to eliminate the MYD
> file for a table that has a full covering index? The index is larger
> than the datafile, since it contains all the records in the datafile,
> plus a second reverse index.  It seems redundant to have to also store
> a MYD file.
> 
> Thanks,
> 
> -Hank
> 
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