Generic "Can I extend?" check

I've been asked to write a generic routine to determine if a segment can extend. Easy enough except for auto-alloc lmt's where 'next_extent' is null (ie indeterminate) in xxx_SEGMENTS.

So here is my current compromise (in pseudo-code)

where nvl(next_extent,
  case

    when initial_extent < 1m then
      case when extents < 16 then next = 64k,
           when extents < 80 then next = 1m,
           when extents < 200 then next = 8m,
           else next = 64m
    when initial_extent >= 1m then
      case when extents < 64 then next = 1m,
           when extents < 184 then next = 8m,
           else next = 64m ) 

The rough translation being:
- auto-alloc extents are 16x64k, then 64x1m, then 120x8m, then 64m, when the initial_extent is less than 1m
- auto-alloc extents are 64x1m, then 120x8m, then 64m, when the initial_extent is equal/more than 1m

In the spirit of "open source", I'm throwing this out the community asking for counter-examples which break the above formula.

Thanks
Connor

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Connor McDonald

http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue..."