GIST optimization to limit calls to operator on sub nodes

Поиск
Список
Период
Сортировка
От Pujol Mathieu
Тема GIST optimization to limit calls to operator on sub nodes
Дата
Msg-id 53A7D547.5080302@realfusio.com
обсуждение исходный текст
Ответы Re: GIST optimization to limit calls to operator on sub nodes
Список pgsql-performance
Hello,
I already post my question in the General Mailing list, but without
succeed so I try this one that seems to me more specialized.
My question is about GIST index.
I made my own index to handle specific data and operators. It works
pretty fine but I wonder if it was possible to optimize it.
When I run my operator on a GIST node (in the method
gist_range_consistent) it returns "NotConsistent" / "MaybeConsistent" /
"FullyConsistent".
NotConsistent -> means that all subnodes could be ignored,
gist_range_consistent return false
MaybeConsistent -> means that at least one subnode/leaf will be
consistent, gist_range_consistent return true
FullyConsistent -> means that all subnodes/leaves will be consistent,
gist_range_consistent return true

So like with the "recheck flag" I would like to know if there is a way
to notify postgres that it is not necessary to rerun my operator on
subnodes, to speedup the search.

For example, consider the following gist tree
           R
     /         \
    Na          Nb
  /   \       /    \
La1  La2    Lb1  Lb2

If all nodes return FullyConsistent, postgres will run tests in that
Order : R, Na, Nb, La1, La2, Lb1, Lb2, thanks to recheck flag it will
not test rows associated to leaves Lxx.
My goal is that postgres run test on R and then skip tests on other
nodes. So is there a way to do that in the GIST API ? Or could I share
data from R to Nx and then From Na to Lax and Nb to Lbx ?
Thanks,
Mathieu



В списке pgsql-performance по дате отправления:

Предыдущее
От: "Tomas Vondra"
Дата:
Сообщение: Re: huge pgstat.stat file on PostgreSQL 8.3.24
Следующее
От: tim_wilson
Дата:
Сообщение: Re: autovacuum vacuum creates bad statistics for planner when it log index scans: 0