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why the data_length doesn't decrease when I delete some records? | Thread profile

Thread profile page for "why the data_length doesn't decrease when I delete some records?" on http://www.mysql.com. This report page is a snippet summary view from a single thread "why the data_length doesn't decrease when I delete some records?", located on the Message Board at http://www.mysql.com. This thread profile page shows the thread statistics for: Total Authors, Total Thread Posts, and Thread Activity, which are reported in a table below. Additional thread profile information is also shown in the following ways:

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Title: why the data_length doesn't decrease when I delete some records?
Site: MySQL AB - MySQL Forums  MySQL AB - MySQL Forums - site profile
Forum: Newbie   Newbie - forum profile
Total authors: 3 authors
Total thread posts: 4 posts
Thread activity: no new posts during last week
Domain info for: mysql.com

Thread posts in why the data_length doesn't decrease when I delete some records?:

1. 
Started 2 years, 3 months ago (2007-03-14 21:19:00)  by grass grass
I'm using MyISam as the data engine. I first created a table, the the data_length was initially 0. Then I added 10 records and the data_length became 170. But after I deleted all the 10 records, the data_length still remained 170. Can anybody explain this? Thanks!
Size: 264 bytes
Customize:  Customize "why the data_length doesn't decrease when I delete some records? :: Newbie :: MySQL AB - MySQL Forums"
2. 
Started 2 years, 3 months ago (2007-03-15 03:59:00)  by Victoria Reznichenko
Because data is not really removed, just marked as 'deleted' and re-used later.
Size: 79 bytes
Customize:  Customize "<b>Reply 1</b>: Re: why the data_length doesn't decrease when I delete some records? :: Newbie :: MySQL AB - MySQL Forums"
3. 
Started 2 years, 3 months ago (2007-03-15 05:20:00)  by Bob Abraham
And what if i want to really delete some records and to decrease database size? Is there any "compress" utility in MySql?
Size: 138 bytes
Customize:  Customize "<b>Reply 2</b>: Re: why the data_length doesn't decrease when I delete some records? :: Newbie :: MySQL AB - MySQL Forums"
4. 
Started 2 years, 3 months ago (2007-03-15 06:27:00)  by Victoria Reznichenko
OPTIMIZE TABLE: [ dev.mysql.com ]
Size: 130 bytes
Customize:  Customize "<b>Reply 3</b>: Re: why the data_length doesn't decrease when I delete some records? :: Newbie :: MySQL AB - MySQL Forums"
 

Top contributing authors for why the data_length doesn't decrease when I delete some records?

Name
Posts
Victoria Reznichenko
2
user's latest post:
Re: why the data_length...
Published (2007-03-15 06:27:00)
OPTIMIZE TABLE: [ dev.mysql.com ]
grass grass
1
user's latest post:
why the data_length doesn't...
Published (2007-03-14 21:19:00)
I'm using MyISam as the data engine. I first created a table, the the data_length was initially 0. Then I added 10 records and the data_length became 170. But after I deleted all the 10 records, the data_length still remained 170. Can anybody explain this? Thanks!
Bob Abraham
1
user's latest post:
Re: why the data_length...
Published (2007-03-15 05:20:00)
And what if i want to really delete some records and to decrease database size? Is there any "compress" utility in MySql?

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