Re: pg_class.relpages/allvisible probably shouldn't be a int4

Andres Freund wrote:
> On 2014-05-11 23:30:37 +0200, Andres Freund wrote:

> > Yea. I really don't like to take on such a major project to solve a
> > minor problem.
> > What I am thinking about right now is to expose a 'pg_blocknumber'
> > type. That only does very basic operations and implicitly casts to
> > int64. That's probably a much more handleable problem and it also might
> > give us some more experience with unsigned types. Comments?
> 
> As a note towards that: e.g. pageinspect deals with blocknumbers and
> uses int4 for that. That makes accessing the higher blocks really
> awkward...

Sounds like pg_blocknumber could be a good idea, but I wouldn't add the
bigint implicit casts to int64.  We might enlarge BlockNumber to
unsigned 64 bits in the future -- we will regret the implicit casts to
signed int64 then.  Anyway it's not like implicit casts will get us any
extra functionality.  We can just add + and - operators, and that should
cover 99% of what people would initially want ...

Now, adding casts FROM int32 and int64 to pg_blocknumber doesn't sound
bad.  (Maybe have them error out if the value is negative?)

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
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