Re: [GENERAL] Creation of tsearch2 index is very slow - Mailing list pgsql-performance

From Steinar H. Gunderson
Subject Re: [GENERAL] Creation of tsearch2 index is very slow
Date
Msg-id 20060121003646.GA31406@uio.no
Whole thread Raw
In response to Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane)
List pgsql-performance
On Fri, Jan 20, 2006 at 07:23:10PM -0500, Tom Lane wrote:
> I'm not very clear on what tsearch2 is doing with these bitmaps, but it
> looks like an upper page's downlink has the union (bitwise OR) of the
> one-bits in the values on the lower page, and you have to visit the lower
> page if this union has a nonempty intersection with the set you are looking
> for.  If that's correct, what you really want is to divide the values so
> that the unions of the two sets have minimal overlap ... which seems to me
> to have little to do with what the code does at present.

Sort of like the vertex-cover problem? That's probably a lot harder than
finding the two farthest points...

/* Steinar */
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