Gerald,
> >>(in fact it's a bitmap, that is it would be one byte for up to 8
> >>columns, then it'll be 2 bytes, etc.)
> >If so, this table should have an average row length of 92, not 91,
> It does on mine.
Alright, I take this as a Windows goodie (my MySQL 4.0.7 runs on Win2K
;-)
Regards,
--
Stefan Hinz <hinz@stripped>
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: "gerald_clark" <gerald_clark@stripped>
To: "Stefan Hinz" <hinz@stripped>
Cc: "Sergei Golubchik" <serg@stripped>; "Keith C. Ivey"
<keith@stripped>; <mysql@stripped>
Sent: Friday, January 17, 2003 3:48 PM
Subject: Re: Avg_row_length
>
>
> Stefan Hinz wrote:
>
> >Sergei,
> >
> >
> >
> >>>any other guru who can explain why 10 = 11?
> >>>
> >>>
> >
> >
> >
> >>It's because of NULLs.
> >>Extra byte is used to mark, if the column is NULL or not.
> >>
> >>
> >
> >Thanks alot for the explanation. Thanks to Gerald Clark, too, who
told
> >me the same.
> >
> >
> >
> >>(in fact it's a bitmap, that is it would be one byte for up to 8
> >>columns, then it'll be 2 bytes, etc.)
> >>
> >>
> >
> >If so, this table should have an average row length of 92, not 91,
> >
>
> It does on mine.
>
> >shouldn't it (9 cols * 10 bytes + 2 bytes)?
> >
> >MySQL>DESCRIBE myrowisam;
> >+-------+----------+------+-----+---------+-------+
> >| Field | Type | Null | Key | Default | Extra |
> >+-------+----------+------+-----+---------+-------+
> >| col1 | char(10) | | | | |
> >| col2 | char(10) | | | | |
> >| col3 | char(10) | | | | |
> >| col4 | char(10) | | | | |
> >| col5 | char(10) | | | | |
> >| col6 | char(10) | | | | |
> >| col7 | char(10) | | | | |
> >| col8 | char(10) | | | | |
> >| col9 | char(10) | | | | |
> >+-------+----------+------+-----+---------+-------+
> >MySQL>SELECT * FROM myrowisam;
> >+------+------+------+------+------+------+------+------+------+
> >| col1 | col2 | col3 | col4 | col5 | col6 | col7 | col8 | col9 |
> >+------+------+------+------+------+------+------+------+------+
> >| foo | foo | foo | foo | foo | foo | foo | foo | foo |
> >+------+------+------+------+------+------+------+------+------+
> >MySQL>SHOW TABLE STATUS LIKE 'myrowisam';
> >+-----------+--------+------------+------+----------------+
> >| Name | Type | Row_format | Rows | Avg_row_length |
> >+-----------+--------+------------+------+----------------+
> >| myrowisam | MyISAM | Fixed | 1 | 91 |
> >+-----------+--------+------------+------+----------------+
> >
> >Regards,
> >--
> > Stefan Hinz <hinz@stripped>
> > 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: "Sergei Golubchik" <serg@stripped>
> >To: "Stefan Hinz" <hinz@stripped>
> >Cc: "Keith C. Ivey" <keith@stripped>; <mysql@stripped>
> >Sent: Thursday, January 16, 2003 9:16 PM
> >Subject: Re: Avg_row_length
> >
> >
> >
> >
> >>Hi!
> >>
> >>On Jan 16, 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 <hinz@stripped>
> >>> Gesch?ftsf?hrer / CEO iConnect GmbH <http://iConnect.de>
> >>> Heesestr. 6, 12169 Berlin (Germany)
> >>> Tel: +49 30 7970948-0 Fax: +49 30 7970948-3
> >>>
> >>>
> >>It's because of NULLs.
> >>Extra byte is used to mark, if the column is NULL or not.
> >>
> >>(in fact it's a bitmap, that is it would be one byte for up to 8
> >>columns, then it'll be 2 bytes, etc.)
> >>
> >>Regards,
> >>Sergei
> >>
> >>--
> >>MySQL Development Team
> >> __ ___ ___ ____ __
> >> / |/ /_ __/ __/ __ \/ / Sergei Golubchik <serg@stripped>
> >> / /|_/ / // /\ \/ /_/ / /__ MySQL AB, http://www.mysql.com/
> >>/_/ /_/\_, /___/\___\_\___/ Osnabrueck, Germany
> >> <___/
> >>
> >>
> >
> >
> >
> >
> >
>
>
