Re: Data loss, vacuum, transaction wrap-around

"Joshua D. Drake" <jd(at)commandprompt(dot)com> writes:
> Tom Lane wrote:
>> A real fix (eg the forcible stop we were talking about earlier) will not
>> be reasonable to back-port.

> Would at least a automated warning mechanism be a reasonable backport?

No, because the hard part of the problem actually is detecting that the
condition exists in a reasonably cheap way. The check in VACUUM is
really extremely expensive, which is why we don't make it except after
completing a database-wide vacuum. Once we have an XID limit value
sitting in shared memory then the code to use it (generate warnings
and/or error out) is simple; it's initializing that value during
postmaster start that I consider too complicated/risky to stick into
existing versions.

There is another issue here, which is that I have no faith that the
people who actually need this are going to be clueful enough to update
to 7.4.8 or 7.3.10 or whatever they'd need...

regards, tom lane