Thread: 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
Kilian Hagemann <hagemann1@egs.uct.ac.za> writes:
> 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?
Because it will certainly break by 2038, when 32-bit time_t overflows.
In practice, Unix systems will have to move to 64-bit time_t before
that, and we'll probably either remove abstime or make it an 8-byte type
as soon as that practice is common.
regards, tom lane
> > Because it will certainly break by 2038, when 32-bit time_t overflows. > > In practice, Unix systems will have to move to 64-bit time_t before > that, and we'll probably either remove abstime or make it an 8-byte type > as soon as that practice is common. Thanks for that. By that time my storage requirements will certainly have changed, but I guess this transformation won't happen in a hurry... I'd like to see abstime supported until at least 2020. > TIP 5: Have you checked our extensive FAQ? I have, and it doesn't have an entry on this. Don't know who maintains the FAQ, but I think it would be worthwhile adding this issue to the FAQ. -- Kilian Hagemann Climate Systems Analysis Group University of Cape Town Republic of South Africa Tel(w): ++27 21 650 2748
Kilian Hagemann wrote: > > > > Because it will certainly break by 2038, when 32-bit time_t overflows. > > > > In practice, Unix systems will have to move to 64-bit time_t before > > that, and we'll probably either remove abstime or make it an 8-byte type > > as soon as that practice is common. > > Thanks for that. By that time my storage requirements will certainly have > changed, but I guess this transformation won't happen in a hurry... I'd like > to see abstime supported until at least 2020. > > > TIP 5: Have you checked our extensive FAQ? > > I have, and it doesn't have an entry on this. Don't know who maintains the > FAQ, but I think it would be worthwhile adding this issue to the FAQ. It is not an F(frequent)AQ because you are the first to ask about it in perhaps years. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073