Comments on: Max VARCHAR Size http://www.pythian.com/news/1353/max-varchar-size/ News and views from Pythian DBAs Fri, 10 Feb 2012 13:01:25 +0000 hourly 1 http://wordpress.org/?v=3.0.4 By: Artículos destacados, Noviembre de 2008 | cambrico.net http://www.pythian.com/news/1353/max-varchar-size/#comment-309845 Artículos destacados, Noviembre de 2008 | cambrico.net Sat, 06 Dec 2008 13:30:35 +0000 http://www.pythian.com/blogs/1353/max-varchar-size#comment-309845 [...] sobre el tamaño del VARCHAR, en pythian group (en [...] [...] sobre el tamaño del VARCHAR, en pythian group (en [...]

]]> By: Arjen Lentz http://www.pythian.com/news/1353/max-varchar-size/#comment-298172 Arjen Lentz Sat, 08 Nov 2008 23:08:57 +0000 http://www.pythian.com/blogs/1353/max-varchar-size#comment-298172 ...and then there's UTF8... TEXT/BLOB types of course cause disk I/O when tmp tables are needed during query execution, so using longer VARCHARs can generally be a good thing. …and then there’s UTF8…

TEXT/BLOB types of course cause disk I/O when tmp tables are needed during query execution, so using longer VARCHARs can generally be a good thing.

]]> By: Mark Atwood http://www.pythian.com/news/1353/max-varchar-size/#comment-298170 Mark Atwood Sat, 08 Nov 2008 23:02:47 +0000 http://www.pythian.com/blogs/1353/max-varchar-size#comment-298170 The additional overhead you discovered is the null mask. There will be one byte of null mask for every 8 potentially nullable columns. Your test table has 8 or less nullable columns, so you got one byte. If you have 24 columns that can have nulls, you would have 3 bytes. And so forth. The additional overhead you discovered is the null mask. There will be one byte of null mask for every 8 potentially nullable columns. Your test table has 8 or less nullable columns, so you got one byte. If you have 24 columns that can have nulls, you would have 3 bytes. And so forth.

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