Re: [GENERAL] Creation of tsearch2 index is very slow

gevel is available from
http://www.sai.msu.su/~megera/postgres/gist/

     Oleg
On Sat, 21 Jan 2006, Martijn van Oosterhout wrote:

> On Sat, Jan 21, 2006 at 04:29:13PM +0300, Oleg Bartunov wrote:
>> Martijn, you're right! We want not only to split page to very
>> different parts, but not to increase the number of sets bits in
>> resulted signatures, which are union (OR'ed) of all signatures
>> in part. We need not only fast index creation (thanks, Tom !),
>> but a better index. Some information is available here
>> http://www.sai.msu.su/~megera/oddmuse/index.cgi/Tsearch_V2_internals
>> There are should be more detailed document, but I don't remember where:)
>
> I see how it works, what I don't quite get is whether the "inverted
> index" you refer to is what we're working with here, or just what's in
> tsearchd?
>
>>> That's harder though (this algorithm does approximate it sort of)
>>> and I havn't come up with an algorithm yet
>>
>> Don't ask how hard we thought :)
>
> Well, looking at how other people are struggling with it, it's
> definitly a Hard Problem. One thing though, I don't think the picksplit
> algorithm as is really requires you to strictly have the longest
> distance, just something reasonably long. So I think the alternate
> algorithm I posted should produce equivalent results. No idea how to
> test it though...
>
> Have a nice day,
>

     Regards,
         Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83