Block Sizes

Oracle has adjustable disk block sizes, tuneable per instance
(can you change it after install??  can't remember).  In any
case the default is 2k or 4k, and things almost always go
faster with larger block sizes.  On one project we needed to
go fast and had disk space to burn, so we upped it to 16k.
This was all _without_ using raw devices.

My *gut* feeling is that the underlying block size is a trade-off,
smaller blocks are better for small transactions, bigger blocks
are better for bulk load/extract operations, with a penalty for 
finding a single row.  Optimum depends on the application, but is
somewhere between 2 and 32 k.

How hard would it be for postgresql to support adjustable block sizes? 
Just wondering.

-- cary
cobrien@access.digex.net