Обсуждение: Bizarre coding in recovery target GUC management

Would someone explain to me why assign_recovery_target_lsn and related GUC
assign hooks throw errors, rather than doing so in the associated check
hooks?  An assign hook is not supposed to throw an error.  Full stop, no
exceptions.  We wouldn't bother to separate those hooks otherwise.

            regards, tom lane

On 2020-10-12 18:00, Tom Lane wrote:
> Would someone explain to me why assign_recovery_target_lsn and related GUC
> assign hooks throw errors, rather than doing so in the associated check
> hooks?  An assign hook is not supposed to throw an error.  Full stop, no
> exceptions.  We wouldn't bother to separate those hooks otherwise.

That code is checking whether more than one recovery target GUC has been 
set.  I don't think the check hook sees the right state to be able to 
check that.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
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