Re: unique row identifier data type exhausted . . .

Frank Joerdens wrote:

> It feels like there should be some *really* obvious answer to this
> question, and I'll find myself whacking my forehead in self-abasement
> and out of sheer relief to have found the answer to a problem that
> should not have bothered me in the first place since the answer is too
> self-evident . . . however, it is bothering me: what happens if the data
> type that you've chosen to uniquely identify a row is exhausted? If, for
> instance you use int4 and you've had your couple billion deletes and
> inserts on the table and the next nextval('seq') . . . well, what
> exactly happens and how do they do it? Admittedly, 10^9 is a big number
> but it is far from out of the question that you'd reach it on a really
> busy database (can't think of a real-world example but that ought to be
> a moot point), not to mention oids since they are unique across an
> entire database.

This is the command to create a sequence :

CREATE SEQUENCE seqname
    [ INCREMENT increment ]
    [ MINVALUE  minvalue ]
    [ MAXVALUE  maxvalue ]
    [ START     start ]
    [ CACHE     cache ]
    [ CYCLE ]

The CYCLE option restarts the sequence automatically upon overflow. Of
course, your analysis of the database should point out that it is possible
to do this.

Jurgen Defurne
defurnj@glo.be