On Mon, Feb 11, 2002 at 04:48:10PM -0600, David Felio wrote: > Whoops, originally sent this to just Heikki. > > On Monday, February 11, 2002, at 12:12 PM, Heikki Tuuri wrote: > >> for InnoDB 'dynamic rows', that is, rows where you define char columns as >> VARCHAR, are faster because tables and indexes fit in smaller space. > > Is there reasoning specific to InnoDB?
Sort of. It's because InnoDB stores the data and indexes together. (BDB does something similar.) > Dynamic tables would be smaller regardless of the table type, I > would think. True. > In Kaj Arno's talk on optimizing MySQL at the O'Reilly Open Source > Convention last year, he said that fixed tables are preferable and > that if you must have dynamic columns, you should try to put them in > a table separate from your static columns (slides 67 and 68 for > those who have them). Has this changed? Nope, not for MyISAM it hasn't changed. With fixed rows, tables can be checked, repaired, and accessed more quickly. If you know the row size, you know how to get to row 500,123 quickly. It's just multiplication. But if the row sizes are all different, you have to scan the rows before it. (This is an over-simplification, but hopefully gets the point across.) Plus, if you have fixed rows and no "holes" in the table, you can INSERT and SELECT at the same time. :-) So, Kaj's talk is right on. Going to the conference again this year? There's gonna be some cool MySQL stuff again this year. Jeremy -- Jeremy D. Zawodny, <[EMAIL PROTECTED]> Technical Yahoo - Yahoo Finance Desk: (408) 349-7878 Fax: (408) 349-5454 Cell: (408) 685-5936 MySQL 3.23.47-max: up 4 days, processed 162,876,748 queries (418/sec. avg) --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
