From: Date: July 4 2009 5:55pm
Subject: Re: How to recover from online DDL failure?
List-Archive: http://lists.mysql.com/internals/37092
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Hi!

On Jul 4, 2009, at 8:04 AM, Ingo Str=FCwing wrote:

> If the data dictionary is in the engine, how do you know, which engine
> serves a certain table?

Engines are asked in order, with the default being first, about who =20
has the table (assuming it is not already in the TableShare cache). =20
The default implementation is only called once (aka... backup DFE for =20=

engines which lack a dictionary).

Seeing how the vast majority use just one engine the hit cost is =20
practically the same as having just one centralized system. Toss in =20
the relatively few numbers of tables compared to the size of the =20
TableCache and... you never see a issue.

At some point the cache itself will be pushed down for the engine to =20
be able to handle as well, this allows a greater degree of ability for =20=

online operations.

Cheers,
	-Brian=