Greg Stark <[EMAIL PROTECTED]> writes:
> The approach they take is to have a function which calculates an
> abstract "distance" between any two entries. There's an algorithm that
> they use to pick the split based on this distance function.
> If you abandoned "PickSplit" and instead exposed this d
Greg Stark <[EMAIL PROTECTED]> writes:
> I'm not sure that GiST indexes behave the same way as btree indexes for the
> multi-column case.
>
> In a btree index the second column is entirely subordinate to the first
> column. In a GiST index the data is multi-dimensional, and all dimensions are
>
Tom Lane <[EMAIL PROTECTED]> writes:
> If there are no don't-care cases, then you're effectively saying that
> the first column's PickSplit has sole control over the tree shape,
> which is where we're at now. ISTM the entire point of a multi-column
> index is that the first column has duplicates
Neil Conway <[EMAIL PROTECTED]> writes:
> On Mon, 2004-11-15 at 10:19 -0500, Tom Lane wrote:
>> I'm not familiar with the details of the GiST code, but would it work to
>> generalize PickSplit to return a three-way classification? That is,
>> instead of actually splitting the node, have it identif
On Mon, 2004-11-15 at 10:19 -0500, Tom Lane wrote:
> I'm not familiar with the details of the GiST code, but would it work to
> generalize PickSplit to return a three-way classification? That is,
> instead of actually splitting the node, have it identify each item as
> "definitely left", "definite
Neil Conway <[EMAIL PROTECTED]> writes:
> I'm not sure the right way to fix it (at least without significant
> changes to the GiST API). At present, the PickSplit() method is passed a
> vector of GISTENTRYs and fills in a GIST_SPLITVEC. The GISTENTRYs
> correspond to the first attributes of all the
Neil,
I think we should not touch this right now unless you certainly know
algorithm proven to be good in general case. Did you already got some idea ?
Oleg
On Mon, 15 Nov 2004, Neil Conway wrote:
On Sun, 2004-11-14 at 18:54 -0500, Tom Lane wrote:
It's probably just a hangover from the days
On Sun, 2004-11-14 at 18:54 -0500, Tom Lane wrote:
> It's probably just a hangover from the days when GiST didn't support
> multi-column indexes at all. I agree it should be changed.
I'm not sure the right way to fix it (at least without significant
changes to the GiST API). At present, the PickS
Neil Conway <[EMAIL PROTECTED]> writes:
> If I understand the code correctly, GiST will only pass the first
> attribute of each index tuple to the user-defined PickSplit method when
> it wants to split a node. (see circa line 1269 of gist.c)
> Is this a wise design decision?
It's probably just
Oleg & Teodor,
If I understand the code correctly, GiST will only pass the first
attribute of each index tuple to the user-defined PickSplit method when
it wants to split a node. (see circa line 1269 of gist.c)
Is this a wise design decision? Granted, in many situations the first
attribute in t
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