Why is abstime type deprecated?

Hi there,

Firstly, I am new to PostgreSQL but installed it recently because of its many
virtues for a project of mine. This is not a bug-report but rather a concern
about the development course of postgresql (hope this is the right place to
post this... please excuse me if it's not).

I am busy storing lots of weather station data into a database, each record
having a timestamp. Now the 'timestamp' type that PostgreSQL (and MySQL for
that matter) offers is 8 bytes long. Space is of the essence, and I found
that if I could use a 4 byte timestamp instead I could reduce the amount of
real (non-overhead) data in my db by 33%.

After long googling I found that abstime, as was still current in 6.x, would
do the trick for me. But the 7.x documentation says "You are discouraged from
using these types in new applications" and that "Any or all of these internal
types might disappear in a future release". The Version 8.0 History file
makes no indication of abstime disappearing, but I'm still worried about
implementing my database with abstime. Why is it deprecated? If it's not, why
does the documentation say it is?

I believe SQL standards come into play here but one could always keep abstime
as a PostgreSQL extension...

I don't need more than 1s resolution and such a type ideally satisfies the
requirements of my application. Quite frankly, I think that there aren't many
people out there who would require a microsecond precision and a date range
of 292000 years into the future...

Regards,

--
Kilian Hagemann

Climate Systems Analysis Group
University of Cape Town
Republic of South Africa
Tel(w): ++27 21 650 2748