Re: DROP COLUMN

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Tom Lane wrote:
> >> Definitely *not*; I don't want to kluge up every call to SearchSysCache
> >> with a feature that's only relevant to a small number of them.
> 
> > Uh, then what?
> 
> Then we make a wrapper function.  Something like
> 
>     GetUndeletedColumnByName(relid,attname)
> 
> replaces SearchSysCache(ATTNAME,...) in those places where you don't
> want to see deleted columns.  It'd return NULL if it finds a column
> tuple but sees it's deleted.
> 
>     GetUndeletedColumnByNum(relid,attnum)
> 
> replaces SearchSysCache(ATTNUM,...) similarly.

Good idea.

> > My only other idea is to make a syscache that is like ATTNAME except
> > that it doesn't return a dropped column.
> 
> That would mean duplicate storage of tuples inside the catcache...

No, I was thinking of something that did the normal ATTNAME lookup in
the syscache code, then returned NULL on dropped columns;  similar to
your idea but done inside the syscache code rather than in a separate
function.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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