Re: Avg_row_length

[gerald_clark]

It looks to me like 1 bit for deleted, and 1 bit for each column to store NULL.
1 byte for 1-7 fields.
2 bytes for 8-15 fields.

Stefan Hinz wrote:

Keith,

thanks once again! Well, anyone here from the MySQL developer team? Or
any other guru who can explain why 10 = 11?

Here's the problem once again:

mysql> DESCRIBE myrowisam;
+-------+----------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------+------+-----+---------+-------+
| col | char(10) | YES | MUL | NULL | |
+-------+----------+------+-----+---------+-------+
mysql> SHOW TABLE STATUS LIKE 'myrowisam';
+-----------+--------+------------+------+----------------+
| Name | Type | Row_format | Rows | Avg_row_length |
+-----------+--------+------------+------+----------------+
| myrowisam | MyISAM | Fixed | 109 | 11 |
+-----------+--------+------------+------+----------------+

Regards,
--
Stefan Hinz <[EMAIL PROTECTED]>
Geschäftsführer / CEO iConnect GmbH <http://iConnect.de>
Heesestr. 6, 12169 Berlin (Germany)
Tel: +49 30 7970948-0 Fax: +49 30 7970948-3

----- Original Message -----
From: "Keith C. Ivey" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: "Stefan Hinz" <[EMAIL PROTECTED]>
Sent: Thursday, January 16, 2003 5:05 PM
Subject: Re: Avg_row_length

On 16 Jan 2003, at 0:37, Stefan Hinz wrote:

There's a formula to calculate the row length for dynamic MyISAM
tables here:
http://www.mysql.com/doc/en/Dynamic_format.html

Thanks for the hint, but this doesn't explain fixed length row
calculations where char(10) will give an average row length of 11
(bytes), or does it?

You're right, it doesn't. I forgot that you were talking about fixed-
length records. I'm afraid I don't have anything else to add then,
since I know nothing about the storage format other than what I've
seen in the documentation.

[Filter fodder: SQL]

--
Keith C. Ivey <[EMAIL PROTECTED]>
Tobacco Documents Online
http://tobaccodocuments.org
Phone 202-667-6653

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