On 04/10/2011 07:27 PM, Tomas Vondra wrote:
But if you need more details, then I quess the best approach to get it
is to read the sources (search for the cost estimation etc.).
There's a small fully worked out example of this in my book too, where I
duplicate the optimizer's EXPLAIN cost c
There's a quite nice description in the docs:
http://www.postgresql.org/docs/9.0/interactive/row-estimation-examples.html
and a some more details for indexes:
http://www.postgresql.org/docs/9.0/interactive/index-cost-estimation.html
A bit more info about how this is used is available in this pr
Dear ,all
i would to ask you about how postgresql optimizer parameters :-
1- random page cost
2- cpu tuple cost3- cpu operator cost4- cpu index tuple cost5- effective cache
size
play as parameters in cost estimator equation
i imagine that cost function is the same as
f(x,y,z,)=ax+by..
c
