Le 29/06/2014 22:14, Emre Hasegeli a écrit :
Pujol Mathieu <mathieu.pujol@xxxxxxxxxxxxx>:
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.
I do not think it is possible at the moment. The GiST framework can
be extended to support this use case. I am not sure about the
speedup. Most of the consistent functions do not seem very expensive
compared to other operations of the GiST framework. I would be
happy to test it, if you would implement.
Thanks for your reply.
I am not sure to have time to develop inside the framework, but if I try
I'll let you know my results. In my case the consistent function is
costly and the number of row important so this optimization could save
several hundred tests on a single request.
--
Mathieu PUJOL
Ingénieur Réalité Virtuelle
REAL FUSIO - 3D Computer Graphics
10, rue des arts - 31000 TOULOUSE - FRANCE
mathieu.pujol@xxxxxxxxxxxxx - http://www.realfusio.com
