
> The cost estimation code is under active development, and if you check
> the pgsql list archives you will find lively discussions about its
> deficiencies ;-).  But I'm having a hard time mustering much concern
> about whether it behaves optimally in the vacuum-but-no-vacuum-analyze
> case.

Here I must slightly disagree, if the impact of vacuum without analyze is so
bad,
then analyze should be the default for vacuum.

Maybe a better default selectivity would be datatype driven, like

int: 1/(2*maxint)
char(n): 1/(n*256)
....
I think this is what my favorite commercial DBMS does.

Because we have an extensible type system I guess this would be overdoing
it,
but in this light a much smaller default selectivity would seem more
appropriate 
(like 1/100000).

Andreas

Thu, 25 May 2000 10:31:59 +0200
Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at>
AW: More Performance 