Re: How to avoid transaction ID wrap

Zdenek Kotala <Zdenek.Kotala@Sun.COM> writes:
> Koichi Suzuki wrote:
>> I've once proposed a patch for 64bit transaction ID, but this causes 
>> some overhead to each tuple (XMIN and XMAX).

> Did you check performance on 32-bit or 64-bit systems and 64-bit binary 
> version of PGSQL? I think that today is not problem to have 64-bit 
> architecture and 64-bit ID should increase scalability of Postgres.

The percentage increase in I/O demand is the main reason the patch was
rejected, not so much the arithmetic.
        regards, tom lane