Re: On partitioning

On 2014-08-29 13:15:16 -0400, Tom Lane wrote:
> Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> > Tom Lane wrote:
> >> One other interesting thought that occurs to me: are we going to support
> >> UPDATEs that cause a row to belong to a different partition?  If so, how
> >> are we going to handle the update chain links?
> 
> > Bah, I didn't mention it?  My current thinking is that it would be
> > disallowed; if you have chosen your partitioning key well enough it
> > shouldn't be necessary.  As a workaround you can always DELETE/INSERT.
> > Maybe we can allow it later, but for a first cut this seems more than
> > good enough.
> 
> Hm.  I certainly agree that it's a case that could be disallowed for a
> first cut, but it'd be nice to have some clue about how we might allow it
> eventually.

Not pretty, but we could set t_ctid to some 'magic' value when switching
partitions. Everything chasing ctid chains could then error out when
hitting a invisible row with such a t_ctid.  The usecases for doing such
updates really are more maintenance style commands, so it's possibly not
too bad from a usability POV :(

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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