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From:Paul DuBois Date:May 29 2006 6:00pm
Subject:Re: max size of TEXT columns
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At 17:06 +0200 5/29/06, schlubediwup wrote:
>2. problem
>according do the mysql docu TEXT/BLOB fields depend solely on the db 
>environment and can grow to any length:
>
>
>      11.4.3. The |BLOB| and |TEXT| Types
>
>
>....
>The maximum size of a |BLOB| or |TEXT| object is determined by its type, but

"determined by its type" is correct.
"to any length" is incorrect.

The maximum lengths are described here:

http://dev.mysql.com/doc/refman/5.0/en/string-type-overview.html
http://dev.mysql.com/doc/refman/5.0/en/storage-requirements.html



>the largest value you actually can transmit between the client and 
>server is determined by the amount of available memory and the size 
>of the communications buffers. You can change the message buffer 
>size by changing the value of the |max_allowed_packet| variable, but 
>you must do so for both the server and your client program. For 
>example, both *mysql* and *mysqldump* allow you to change the 
>client-side |max_allowed_packet| value. See Section 7.5.2, "Tuning 
>Server Parameters" 
><http://www.ayni.com/mysql/optimization.html#server-parameters>, 
>Section 8.3, "mysql - The MySQL Command-Line Tool" 
><http://www.ayni.com/mysql/client-side-scripts.html#mysql>, and 
>Section 8.8, "mysqldump - A Database Backup Program" 
><http://www.ayni.com/mysql/client-side-scripts.html#mysqldump>.
>
>....
>
>BUT:
>
>The table in consideration contains a column named history 
>containing all message text which has been sent to the mail-address 
>in the row in question. i ment to have observed that this column in 
>reality does not contain all message text from the very beginning. 
>today, i found out that the maximum lenght of the history fields in 
>all tables of this kind is 65535.
>
>when an update is ocurring, the column history is recreated using 
>concat(new_text, history) so that the newest text is always at the 
>beginning of the column. but the oldest text at the end of the 
>column apparently is lost.
>
>3. question
>
>which parameter do i have to change in order to get this TEXT column 
>really to any length?
>
>any hint is very much appreciated, thanks in advance.
>
>suomi
>
>
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-- 
Paul DuBois, MySQL Documentation Team
Madison, Wisconsin, USA
MySQL AB, www.mysql.com
Thread
max size of TEXT columnsschlubediwup29 May
  • Re: max size of TEXT columnsPaul DuBois29 May
RE: max size of TEXT columnsRobert DiFalco29 May