On Mon, Jun 14, 2021 at 12:10 PM Tomas Vondra
wrote:
> >> I haven't read the [Kossmann & Stocker, 2000] paper yet, but the
> >> [Neumann, 2018] paper seems to build on it, and it seems to work with
> >> much larger subtrees of the join tree than k=5.
> >
> > Right, in particular it builds on "IDP
Hi,
I stumbled across this which may be of interest to this topic and GEQO
alternative.
The main creator/author of Neo and Bao (ML for Query Optimizer) Ryan Marcus
(finishing Postdoc and looking for job) recently posted [1] about Bao for
distributed systems.
But what was interesting was
On Wed, Jun 16, 2021 at 12:01 PM Robert Haas wrote:
>
> I feel like these are completely equivalent. Either way, the planner
> is going to deduce that all the ".col" columns are equal to each other
> via the equivalence class machinery, and then the subsequent planning
> will be absolutely identic
John Naylor writes:
> On Wed, Jun 16, 2021 at 12:01 PM Robert Haas wrote:
>> I feel like these are completely equivalent. Either way, the planner
>> is going to deduce that all the ".col" columns are equal to each other
>> via the equivalence class machinery, and then the subsequent planning
>> w
On Wed, Jun 16, 2021 at 12:01 PM Robert Haas wrote:
>
> On Tue, Jun 15, 2021 at 2:16 PM John Naylor
> wrote:
> > > I don't quite understand the difference between the "chain" case and
> > > the "star" case. Can you show sample queries for each one? e.g. SELECT
> > > ... FROM a_1, a_2, ..., a_n WH
On Tue, Jun 15, 2021 at 2:16 PM John Naylor
wrote:
> > I don't quite understand the difference between the "chain" case and
> > the "star" case. Can you show sample queries for each one? e.g. SELECT
> > ... FROM a_1, a_2, ..., a_n WHERE ?
>
> SELECT *
> FROMtab1, tab2, tab3, tab4
> WHERE ta
On Tue, Jun 15, 2021 at 12:15 PM Robert Haas wrote:
>
> On Wed, Jun 9, 2021 at 9:24 PM John Naylor
wrote:
> > 3) It actually improves the existing exhaustive search, because the
complexity of the join order problem depends on the query shape: a "chain"
shape (linear) vs. a "star" shape (as in sta
On Tue, Jun 15, 2021 at 1:00 PM Tom Lane wrote:
> Still, I take your point that maybe we could ratchet down the cost of
> exhaustive search by skimping on this part. Maybe it'd work to skip
> bushy so long as we'd found at least one left-deep or right-deep path
> for the current rel.
Yes, that s
Robert Haas writes:
> One idea I just ran across in
> https://15721.courses.cs.cmu.edu/spring2020/papers/22-costmodels/p204-leis.pdf
> is to try to economize by skipping consideration of bushy plans. We
> could start doing that when some budget is exceeded, similar to what
> you are proposing here
On Wed, Jun 9, 2021 at 9:24 PM John Naylor wrote:
> 3) It actually improves the existing exhaustive search, because the
> complexity of the join order problem depends on the query shape: a "chain"
> shape (linear) vs. a "star" shape (as in star schema), for the most common
> examples. The size
On Mon, Jun 14, 2021 at 06:10:28PM +0200, Tomas Vondra wrote:
> On 6/14/21 1:16 PM, John Naylor wrote:
> > On Sun, Jun 13, 2021 at 9:50 AM Tomas Vondra
> > mailto:tomas.von...@enterprisedb.com>>
> > wrote:
> >
> >> > 2) We can still keep GEQO around (with some huge limit by default) for a
> >> > f
On 6/14/21 1:16 PM, John Naylor wrote:
> On Sun, Jun 13, 2021 at 9:50 AM Tomas Vondra
> mailto:tomas.von...@enterprisedb.com>>
> wrote:
>
>> > 2) We can still keep GEQO around (with some huge limit by default) for a
>> > few years as an escape hatch, while we refine the replacement. If there
>>
On Sun, Jun 13, 2021 at 9:50 AM Tomas Vondra
wrote:
> > 2) We can still keep GEQO around (with some huge limit by default) for a
> > few years as an escape hatch, while we refine the replacement. If there
> > is some bug that prevents finding a plan, we can emit a WARNING and fall
> > back to GEQ
Hi,
On 6/10/21 3:21 AM, John Naylor wrote:
> Hi,
>
> On occasion it comes up that the genetic query optimizer (GEQO) doesn't
> produce particularly great plans, and is slow ([1] for example). The
> only alternative that has gotten as far as a prototype patch (as far as
> I know) is simulated anne
Hi,
On occasion it comes up that the genetic query optimizer (GEQO) doesn't
produce particularly great plans, and is slow ([1] for example). The only
alternative that has gotten as far as a prototype patch (as far as I know)
is simulated annealing some years ago, which didn't seem to get far.
The
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