Em Monday 04 February 2008 07:03:47 Dawid Kuroczko escreveu: > On Feb 4, 2008 5:14 AM, Alex Turner <armtuk@xxxxxxxxx> wrote: > > I"m not a database expert, but wouldn't > > [...] > > > give you a lot less pages to load than building a table with say 90 > > columns in it that are all null, which would result in better rather than > > worse performance? > > Well, but PostgreSQL's NULLs occupy almost no space, or rather a bit of > space, that is one bit exactly. ;-) I am pretty much sure that > storage-wise looking NULLs > are more efficient. I'd say 1 byte every 8 NULLs instead of 1 bit. If you only have 1 NULL, it will cost you 1 byte (not 1 bit). If you have 9, it will cost you 2 bytes (not 9 bits). -- Jorge Godoy <jgodoy@xxxxxxxxx> ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
