Re: XID wraparound and busy databases

On Wednesday 15 August 2007 09:49:52 Tom Lane wrote:
> Heikki Linnakangas <heikki(at)enterprisedb(dot)com> writes:
> > Maybe we can do something to reduce the xid consumption? For example,
> > reuse xids for read-only queries.
>
> Hmm, that's an idea.
>
> More simply, just keep the current transaction open (resetting
> everything but the XID) if we have made no changes by the time we're
> told to commit or rollback ... which is something we track already,
> so as not to waste cycles on useless commit XLOG records.

Jan and myself were discussing something like this as it would relate to a
subscribe process for slony.

Jan care to summerize your thoughts on this?

>
> You'd want some upper limit on transaction lifetime, so as to avoid the
> "long lived transactions hurt VACUUM" problem, but even reusing a single
> xact for a few seconds would pretty much eliminate this issue, I bet.
> It's hard to see how anyone could be doing 6K xacts/sec unless most are
> read-only.
>
> regards, tom lane
>
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