On Tuesday 27 September 2005 11:59, Pooly wrote: > 2005/9/27, Ow Mun Heng <[EMAIL PROTECTED]>: > > Is there any doc looking at benchmarks of a database which is populated > > entirely with fixed length char compared to variable character lengths? > > > > I know using char is preferred over varchar when it comes to speed. Is > > there any available benchmarks available? > > I guess benchmarks depends on your data... > varchar take really less space, and so is faster to read from disk, so > you could improve speed in having varchar ! But since it cause dynamic > row format, it can makes think slower. >
The MySQL Certification Study Guide states: "For InnoDB tables, it is also true that CHAR columns take more space on average than VARCHAR. But there is no retrieval speed advantage for InnoDB as there is with MyISAM, because the InnoDB engine implements storage for both CHAR and VARCHAR in a similar way. In fact, retrieval of CHAR values might be slower because on average they require more information to be read from disk." (p. 414). So your mileage depends on storage engine, too. -- </Martijn> -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
