Re: storage engine access to serialized version of a TABLE or TABLE_SHARE?

[Dmitry Lenev]

Hello, Zardosht, Sergei!

* Sergei Golubchik <serg@stripped> [11/03/29 10:57]:
> Hi, Zardosht!
> 
> On Mar 28, Zardosht Kasheff wrote:
> > Hello all,
> > 
> > Is there a way for the storage engine to get some sort of byte stream
> > that represents a serialized version of a TABLE or TABLE_SHARE object?
> > The goal is to save it locally during handler::create and then check
> > its contents (as a sanity check) with the TABLE_SHARE passed in during
> > handler::open.
> > 
> > Is this possible? And if it is, is there a way to take this serialized
> > data and print what the table looks like in user readable form?
> 
> I'm afraid not.
> 
> You can take the generated create table statement, like Stewart
> suggested, or grab the complete frm file, like NDB does. But I think it
> may be possible to construct an ALTER TABLE statement that modifies the
> table definition (frm) only, and your sanity check will fail on the next
> open.

I think the latter approach should work (after all it works for NDB).

In cases when ALTER TABLE statement modifies only table definition (i.e.
only .FRM), we still call handler::ha_create_handler_files() method after
new version of .FRM is installed, in order to inform storage engine about
the fact that .FRM has been changed.

-- 
Dmitry Lenev, Software Developer
Oracle Development SPB/MySQL, www.mysql.com

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