10 messages in com.mysql.lists.mysqlRe: Static or Dynamic rows -- which i...
FromSent OnAttachments
Eric Mayers11 Feb 2002 09:42 
Eric Mayers11 Feb 2002 09:42 
Heikki Tuuri11 Feb 2002 10:11 
Heikki Tuuri11 Feb 2002 10:11 
David Felio11 Feb 2002 14:47 
David Felio11 Feb 2002 14:47 
Jeremy Zawodny11 Feb 2002 18:26 
Heikki Tuuri12 Feb 2002 01:53 
Keith C. Ivey12 Feb 2002 14:49 
David Piasecki18 Mar 2002 09:17 
Subject:Re: Static or Dynamic rows -- which is faster?
From:Heikki Tuuri (Heik@innodb.com)
Date:02/11/2002 10:11:41 AM
List:com.mysql.lists.mysql

Eric,

for InnoDB 'dynamic rows', that is, rows where you define char columns as VARCHAR, are faster because tables and indexes fit in smaller space.

Only in some rare cases where you want to avoid fragmentation caused by updates which change a column length, a fixed-length CHAR(...) column can be a better option.

I guess also for MyISAM dynamic rows are usually faster, because you win in smaller disk i/o.

Best regards,

Heikki Tuuri Innobase Oy

--- InnoDB - transactions, row level locking, and foreign key support for MySQL See http://www.innodb.com, download MySQL-Max from http://www.mysql.com

"Eric Mayers" wrote in message ...

I have a large data set (15 mil rows) consisting of a datetime column and a char(255) column. I seem to recall seeing something about performance benefits for using static length rows with MyISAM tables, and I've heard some argument for using dynamic length rows (e.g., use varchar rather than char) in InnoDB tables. So for performance sake (assuming no index can be used), which is better for these table types?

I can imagine that using dynamic length would be better in the case of an IO bottleneck, but maybe there is an efficiency gain from knowing where the records start and stop ahead of time..?

Thanks, Eric

uugh. sql.

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