Re: clock_timestamp() and transaction_timestamp() function

Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
> > Tom Lane writes:
> >> This is a nonstarter, as is the previous proposal to have a single
> >> function with an explicit parameter that selects the behavior.  The
> >> reason is that any such function would have to be treated as completely
> >> non-optimizable.
>
> > Why?  We would just need to ensure that the mode cannot be changed at
> > critical times.
>
> "critical time" being anywhere within a session, I guess?  Either that
> or keep track of whether any cached plans depend on the stability
> assumption.

Ewe, that isn't going to work --- making the value unchangable during the
session.

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