On 8/1/2024 16:21, Alexander Cheshev wrote:
Hi Andrei,
Maybe my wording needed to be more precise. I didn't implement
multidimensional histograms before, so I don't know how expensive they
are. I meant that for dependency statistics over about six columns, we
have a lot of combinations to compu
Hi Andrei,
> Maybe my wording needed to be more precise. I didn't implement
> multidimensional histograms before, so I don't know how expensive they
> are. I meant that for dependency statistics over about six columns, we
> have a lot of combinations to compute.
Equi-Depth Histogram in a 6 dimens
On 8/1/2024 01:36, Tomas Vondra wrote:
On 1/7/24 18:26, Andrei Lepikhov wrote:
On 7/1/2024 17:51, Tomas Vondra wrote:
On 1/7/24 11:22, Andrei Lepikhov wrote:
On 7/1/2024 06:54, Tomas Vondra wrote:
It's an interesting are for experiments, no doubt about it. And if you
choose to explore it, tha
Hi Tomas,
> See section 3.2 in this paper (the "view PDF" does not work for me, but
> the "source PDF" does download a postscript):
I believe that you are referring to a dynamic programming approach. It
is a 1-dimensional case! To find an optimal solution in the
M-dimensional case is an NP-hard p
On 1/7/24 23:53, Alexander Cheshev wrote:
> Hi Tomas,
>
>> The thing I was proposing is that it should be possible to build
>> histograms with bins adapted to density in the given region. With
>> smaller buckets in areas with high density. So that queries intersect
>> with fewer buckets in low-d
Hi Tomas,
> The thing I was proposing is that it should be possible to build
> histograms with bins adapted to density in the given region. With
> smaller buckets in areas with high density. So that queries intersect
> with fewer buckets in low-density parts of the histogram.
This is how Equi-Dep
On 1/7/24 18:26, Andrei Lepikhov wrote:
> On 7/1/2024 17:51, Tomas Vondra wrote:
>> On 1/7/24 11:22, Andrei Lepikhov wrote:
>>> On 7/1/2024 06:54, Tomas Vondra wrote:
It's an interesting are for experiments, no doubt about it. And if you
choose to explore it, that's fine. But it's bett
On 7/1/2024 17:51, Tomas Vondra wrote:
On 1/7/24 11:22, Andrei Lepikhov wrote:
On 7/1/2024 06:54, Tomas Vondra wrote:
It's an interesting are for experiments, no doubt about it. And if you
choose to explore it, that's fine. But it's better to be aware it may
not end with a commit.
For the multi
On 1/7/24 11:22, Andrei Lepikhov wrote:
> On 7/1/2024 06:54, Tomas Vondra wrote:
>> It's an interesting are for experiments, no doubt about it. And if you
>> choose to explore it, that's fine. But it's better to be aware it may
>> not end with a commit.
>> For the multi-dimensional case, I propo
On 7/1/2024 06:54, Tomas Vondra wrote:
It's an interesting are for experiments, no doubt about it. And if you
choose to explore it, that's fine. But it's better to be aware it may
not end with a commit.
For the multi-dimensional case, I propose we first try to experiment
with the various algorith
On 1/6/24 01:00, Alexander Cheshev wrote:
> Hi Tomas,
>
>> Another reason was that the algorithm described in the two papers you
>> reference (1988 paper by DeWitt and the evaluation by Carlson and
>> Sutherland from ~2010) is simple but has pretty obvious weaknesses. It
>> processes the column
Hi Tomas,
I am sorry I didn't look into the code carefully. Indeed Postgres uses
Equi-Depth Histogram:
delta = (nvals - 1) / (num_hist - 1);
Regards,
Alexander Cheshev
On Sat, 6 Jan 2024 at 01:00, Alexander Cheshev wrote:
>
> Hi Tomas,
>
> > Another reason was that the algorithm described in
Hi Tomas,
> Another reason was that the algorithm described in the two papers you
> reference (1988 paper by DeWitt and the evaluation by Carlson and
> Sutherland from ~2010) is simple but has pretty obvious weaknesses. It
> processes the columns one by one - first build bucket on column "a",
> th
On 12/27/23 22:19, Tomas Vondra wrote:
> Hello Alexander,
>
> We actually had histograms in the early patches adding multivariate
> statistics [1]. We however ended up removing histograms and only kept
> the simpler types, for a couple reasons.
>
> It might be worth going through the discussion -
Hello Alexander,
We actually had histograms in the early patches adding multivariate
statistics [1]. We however ended up removing histograms and only kept
the simpler types, for a couple reasons.
It might be worth going through the discussion - I'm sure one of the
reasons was we needed to limit t
15 matches
Mail list logo
