Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> On Sun, Sep 04, 2005 at 06:21:51PM -0400, Tom Lane wrote:
>> XID comparison works OK as long as you make sure that all the XIDs
>> extant in the system at any one time are within +/- 2 billion of each
>> other, and so transitivity does hold within that subset. The problem
>> with a btree is that upper-level tree nodes are likely to contain page
>> boundary keys copied from data that vanished some time ago from the
>> underlying table.
> So there would be no problem if a REINDEX was forced every two billion
> transactions, right? (A bit less, I think.)
That seems a bit brute-force, but it'd probably work. (IIRC the
convention we use for vacuuming is to force some activity every 1
billion transactions, because waiting 2 billion leaves no safety
margin.)
regards, tom lane