Re: Information Schema FILES table

Hi Kathryn!

Great to hear somebody else is looking at using it. We spent some time making sure that it's rather flexible.

I've dug up the original WorkLog, so hopefully this helps:

On Tue, 2007-09-11 at 09:30 -0500, Kathryn Steinbrink wrote:
> I am looking at the MySQL documentation and the column definitions for the
> FILES table in the Information Schema. Can you please provide a more
> detailed description of what a new storage engine is to provide for the
> following columns?
>
> UPDATE_COUNT - This is the total count of all update operations performed
> on the file....correct?

UPDATE_COUNT As in MyISAM file header  

                        For all "as in MyISAM file header" columns, 
                        the values will probably be NULL with any 
                        non-MyISAM storage engine that don't store 
                        similar information. 

>
> CREATION_TIME - This is the date and time that the file was created. What
> is the difference between this field and the CREATE_TIME field? What is
> the description of the CREATE_TIME field?
>
> LAST_UPDATE_TIME - This is the date and time when the file was last
> modified. What is the difference between this field and the UPDATE_TIME
> field? What is the description of the UPDATE_TIME field?

CREATION_TIME           As reported by operating system.    
LAST_UPDATE_TIME        As reported by operating system. 
LAST_ACCESS_TIME        As reported by operating system. 

VERSION                 as in INFORMATION_SCHEMA.TABLES   
ROW_FORMAT              as in INFORMATION_SCHEMA.TABLES  
TABLE_ROWS              as in INFORMATION_SCHEMA.TABLES    
AVG_ROW_LENGTH          as in INFORMATION_SCHEMA.TABLES  
DATA_LENGTH             as in INFORMATION_SCHEMA.TABLES    
MAX_DATA_LENGTH         as in INFORMATION_SCHEMA.TABLES    
INDEX_LENGTH            as in INFORMATION_SCHEMA.TABLES    
DATA_FREE               as in INFORMATION_SCHEMA.TABLES    
CREATE_TIME             as in INFORMATION_SCHEMA.TABLES    
UPDATE_TIME             as in INFORMATION_SCHEMA.TABLES    
CHECK_TIME              as in INFORMATION_SCHEMA.TABLES    
CHECKSUM                as in INFORMATION_SCHEMA.TABLES  

So there is a (subtle) difference...

> RECOVER_TIME - What is the description of this field?

Do you need help?

In addition to our free technical library, Pantek provides professional IT services to companies who utilize Open Source software: Learn more about Pantek's Technical Support offerings Place an order for 24/7/365 Technical Support here Learn more about Pantek, who we are, and what we do Chat with a Live Operator Related lists.mysql.com Links announce benchmarks bugs certification cluster commits dotnet gui-tools internals java maxdb myodbc mysql mysqldoc packagers perl plusplus replication win32 Request more information about Pantek

RECOVER_TIME NULL for most storage engines See internals.xml.

> TRANSACTION_COUNTER - What is the description of this field? What
> operations should be included in the count?

TRANSACTION_COUNTER NULL for most storage engines

(I think the idea here is if your engine is per file and has a commit count, it should go here)

> INDEX_LENGTH - What is expected for this field? A file may have more than
> one index.

INDEX_LENGTH as in INFORMATION_SCHEMA.TABLES

> CHECK_TIME - Is this the last time that the file was checked for damage
> and/or repairs, or what is the description of this field?

CHECK_TIME as in INFORMATION_SCHEMA.TABLES

Do you need more help?

In addition to our free technical library, Pantek provides professional IT services to companies who utilize Open Source software: Learn more about Pantek's Technical Support offerings Place an order for 24/7/365 Technical Support here Learn more about Pantek, who we are, and what we do Chat with a Live Operator Related lists.mysql.com Links announce benchmarks bugs certification cluster commits dotnet gui-tools internals java maxdb myodbc mysql mysqldoc packagers perl plusplus replication win32 Request more information about Pantek

> Thank you!

Hope this helps,
stewart

-- 
Stewart Smith, Senior Software Engineer
MySQL AB, www.mysql.com
Office: +14082136540 Ext: 6616
VoIP: 6616@sip.us.mysql.com
Mobile: +61 4 3 8844 332

Jumpstart your cluster:
http://www.mysql.com/consulting/packaged/cluster.html


application/pgp-signature attachment: This is a digitally signed message part